Power Contact Health Assessor Apparatus and Method

ABSTRACT

A system includes a dry contact with a first pair of switchable electrodes, a wet contact with a second pair of switchable electrodes, an arc suppressor, and a controller circuit operatively coupled to the arc suppressor and the first and second pairs of switchable electrodes. The controller circuit is configured to detect a failure of the wet contact and determine a stick duration associated with the first pair of switchable electrodes. The stick duration is based on a duration between an instance when a coil of the dry contact is deactivated and an instance of separation of the first pair of switchable electrodes during deactivation of the coil. The controller circuit generates, in-situ and in real-time, health assessment for the first pair of switchable electrodes based on a comparison of the determined stick duration with an average stick duration associated with a window of observation.

PRIORITY

This application is a continuation of U.S. patent application Ser. No.17/181,083, filed Feb. 22, 2021, which application is a continuation ofU.S. patent application Ser. No. 16/776,131, filed Jan. 29, 2020, nowU.S. Pat. No. 10,964,490 which issued on Mar. 30, 2021, whichapplication claims the benefit of priority to U.S. ProvisionalApplication Ser. No. 62/798,316, filed Jan. 29, 2019; U.S. ProvisionalApplication Ser. No. 62/798,323, filed Jan. 29, 2019; U.S. ProvisionalApplication Ser. No. 62/798,326, filed Jan. 29, 2019; U.S. ProvisionalApplication Ser. No. 62/898,780, filed Sep. 11, 2019, U.S. ProvisionalApplication Ser. No. 62/898,783, filed Sep. 11, 2019, U.S. ProvisionalApplication Ser. No. 62/898,787, filed Sep. 11, 2019, U.S. ProvisionalApplication Ser. No. 62/898,795, filed Sep. 11, 2019, and U.S.Provisional Application Ser. No. 62/898,798, filed Sep. 11, 2019, withthe contents of all of the above-listed applications being incorporatedherein by reference in their entireties.

TECHNICAL FIELD

The present application relates generally to electrical contact healthassessment apparatus and techniques, including electrical contactsconnected in parallel or in series with each other.

BACKGROUND

Product designers, technicians, and engineers are trained to acceptmanufacturer specifications when selecting electromechanical relays andcontactors. None of these specifications, however, indicate the seriousimpact of electrical contact arcing on the life expectancy of the relayor the contactor. This is especially true in high-power (e.g., over 2Amp) applications.

Electrical current contact arcing may have a deleterious effect onelectrical contact surfaces, such as relays and certain switches. Arcingmay degrade and ultimately destroy the contact surface over time and mayresult in premature component failure, lower quality performance, andrelatively frequent preventative maintenance needs. Additionally, arcingin relays, switches, and the like may result in the generation ofelectromagnetic interference (EMI) emissions. Electrical current contactarcing may occur both in alternating current (AC) power and in directcurrent (DC) power across the fields of consumer, commercial,industrial, automotive, and military applications. Because of itsprevalence, there have literally been hundreds of specific meansdeveloped to address the issue of electrical current contact arcing.

SUMMARY

Various examples are now described to introduce a selection of conceptsin a simplified form that is further described below in the detaileddescription. The Summary is not intended to identify key or essentialfeatures of the claimed subject matter, nor is it intended to be used tolimit the scope of the claimed subject matter.

According to a first aspect of the present disclosure, there is providedan electrical circuit including a pair of terminals adapted to beconnected to a set of switchable contact electrodes of a power contact.The electrical circuit further includes a power switching circuitoperatively coupled to the pair of terminals. The power switchingcircuit is configured to switch power from an external power source andto trigger activation of the set of switchable contact electrodes basedon a first logic state signal or deactivation of the set of switchablecontact electrodes based on a second logic state signal. The electricalcircuit further includes a contact separation detector operativelycoupled to the pair of terminals, the contact separation detectorconfigured to determine a time of separation of the set of switchablecontact electrodes of the power contact during the deactivation. Theelectrical circuit further includes a controller circuit operativelycoupled to the pair of terminals, the power switching circuit, and thecontact separation detector. The controller circuit is configured to,for each contact cycle of a plurality of contact cycles of the powercontact within a first observation window, generate the second logicstate signal to trigger the deactivation of the set of switchablecontact electrodes. The controller further determines a contact stickduration associated with the set of switchable contact electrodes. Thecontact stick duration is based on a difference between a time thesecond logic state signal is generated and the time of separation duringthe contact cycle. The controller further determines an average contactstick duration for the first observation window based on the contactstick duration for each contact cycle within the first observationwindow. The controller further configures one or more additionalobservation windows with corresponding average contact stick durationsbased on the average stick duration for the first observation window.The controller further generates a health assessment for the set ofswitchable contact electrodes of the power contact based on a subsequentcontact stick duration determined after the first observation window andthe corresponding average contact stick durations for the one or moreadditional observation windows.

According to a second aspect of the present disclosure, there isprovided a system including a pair of terminals adapted to be connectedto a set of switchable contact electrodes of a power contact. The systemfurther includes a contact separation detector configured to determine atime of separation of the set of switchable contact electrodes duringdeactivation of the power contact. The system further includes acontroller circuit operatively coupled to the pair of terminals and thecontact separation detector. The controller circuit is configured todetermine within a first observation window, a plurality of contactstick durations associated with the set of switchable contactelectrodes. Each contact stick duration of the plurality of contactstick durations is determined during a corresponding contact cycle of aplurality of contact cycles of the power contact within the firstobservation window and is based on a time duration between generation ofa logic state signal triggering the deactivation and the time ofseparation of the set of switchable contact electrodes. An averagecontact stick duration for the first observation window is determined bythe controller based on the plurality of contact stick durations. Thecontroller further configures one or more additional observation windowswith corresponding average contact stick durations. The correspondingaverage contact stick durations are determined based on the averagestick duration for the first observation window. A health assessment forthe set of switchable contact electrodes of the power contact isgenerated based on a subsequent contact stick duration for a contactcycle after the first observation window and the corresponding averagecontact stick durations for the one or more additional observationwindows.

According to a third aspect of the present disclosure, there is provideda method including coupling a contact separation detector to a pair ofterminals of a power contact. The contact separation detector isconfigured to determine a time of separation of a set of switchablecontact electrodes of the power contact during deactivation of the powercontact based on a logic state signal. A controller circuit is coupledto the pair of terminals and the contact separation detector. Thecontroller circuit is configured to determine a plurality of stickdurations associated with the set of switchable contact electrodes. Eachstick duration of the plurality of stick durations is determined duringa corresponding contact cycle of a plurality of contact cycles of thepower contact within a first observation window and is based on a timeduration between generation of the logic state signal triggering thedeactivation and the time of separation of the set of switchable contactelectrodes. An average contact stick duration is determined for thefirst observation window based on the plurality of contact stickdurations. One or more additional observation windows with correspondingaverage contact stick durations are configured. The correspondingaverage contact stick durations are determined based on the averagestick duration for the first observation window. A health assessment forthe set of switchable contact electrodes of the power contact isgenerated based on a subsequent contact stick duration for a contactcycle after the first observation window and the corresponding averagecontact stick durations for the one or more additional observationwindows.

Any one of the foregoing examples may be combined with any one or moreof the other foregoing examples to create a new embodiment within thescope of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. The drawingsillustrate generally, by way of example, but not by way of limitation,various embodiments discussed in the present document.

FIG. 1 is a diagram of a system including a power contact healthassessor, according to some embodiments.

FIG. 2 is a block diagram of an example power contact health assessor,according to some embodiments.

FIG. 3 depicts a logarithmic scale graph of average power contact stickduration for power contact health assessment, according to someembodiments.

FIG. 4 depicts a packaging example of a health assessor, according tosome embodiments.

DETAILED DESCRIPTION

It should be understood at the outset that although an illustrativeimplementation of one or more embodiments is provided below, thedisclosed systems, methods, and/or apparatuses described with respect toFIGS. 1-4 may be implemented using any number of techniques, whethercurrently known or not yet in existence. The disclosure should in no waybe limited to the illustrative implementations, drawings, and techniquesillustrated below, including the exemplary designs and implementationsillustrated and described herein, but may be modified within the scopeof the appended claims along with their full scope of equivalents.

In the following description, reference is made to the accompanyingdrawings that form a part hereof, and in which are shown, by way ofillustration, specific embodiments which may be practiced. Theseembodiments are described in sufficient detail to enable those skilledin the art to practice the inventive subject matter, and it is to beunderstood that other embodiments may be utilized, and that structural,logical, and electrical changes may be made without departing from thescope of the present disclosure. The following description of exampleembodiments is, therefore, not to be taken in a limiting sense, and thescope of the present disclosure is defined by the appended claims.

As used herein, the term “dry contact” (e.g., as used in connection withan interlock such as a relay or contactor) refers to a contact that isonly carrying load current when closed. Such contact may not switch theload and may not make or break under load current. As used herein, theterm “wet contact” (e.g., as used in connection with an interlock suchas a relay or contactor) refers to a contact carrying load current whenclosed as well as switching load current during the make and breaktransitions.

Examples of power contact health assessor and components utilizedtherein and in conjunction with power contact health assessors aredisclosed herein. Examples are presented without limitation and it is tobe recognized and understood that the embodiments disclosed areillustrative and that the circuit and system designs described hereinmay be implemented with any suitable specific components to allow forthe circuit and system designs to be utilized in a variety of desiredcircumstances. Thus, while specific components are disclosed, it is tobe recognized and understood that alternative components may be utilizedas appropriate.

Techniques disclosed herein relate to the design and configuration of apower contact health assessor (e.g., the power contact health assessor 1of FIG. 1 and FIG. 2) to provide an indication of the condition (orhealth) of the contact electrodes of the power contact. The healthassessment determination can be performed based on the contact stickduration or other characteristics derived based on the contact stickduration. More specifically, different windows of observation (WoO) maybe configured where each window is associated with a specific contacthealth condition (e.g., new, good, average, poor, replace, failed). Toconfigure the WoO, a first observation window is configured by measuringthe contact stick duration for a pre-defined number of contact cycles ofa power contact within the window. An average stick duration isdetermined based on the measured stick durations and the number ofcycles within the window. An average stick duration for each subsequentwindow is derived using the contact stick duration of the prior window.For example, the average stick duration of the second window is twicethe average stick duration of the first observation window. The averagestick duration of the third observation window is twice the averagestick duration of the second observation window, and so forth. The lastobservation window is determined when the average stick duration reachesa maximum (pre-configured) threshold value (e.g., when the average stickduration reaches 1000 ms, which is the industry standard for a failedcontact). After the observation windows with corresponding average stickdurations are configured, each window can be associated with a healthassessment characteristic (e.g., as illustrated in FIG. 3, sixobservation windows may be configured for a total of 6 possible healthassessment characteristics). During operation of the power contact,contact stick durations may be periodically measured and referencedagainst the configured observation windows to determine in which windowthe measured stick duration fits, and then determine the correspondinghealth assessment characteristic of the current state of the contactassociated with the measured contact stick duration.

As used herein, the term “stick duration” refers to the time differencebetween coil activation/deactivation (e.g., a relay coil of a relaycontact) and power contact activation/deactivation. In some aspects, thediscussed power contact health assessment operations may be structuredso that such operations may be configured and executed inmicrocontrollers and microprocessors without the need for anexternal/computation apparatus or method. In various examples, the powercontact health assessment operations do not rely on extensivemathematical and/or calculus operations. In some aspects, the drycontactor may be optional for power contact health assessment. The drycontactor may be utilized if high dielectric isolation and extremely lowleakage currents are desired.

Arc suppressor is an optional element for the power contact healthassessor. In some aspects, the disclosed power contact health assessormay incorporate an arc suppression circuit (also referred to as an arcsuppressor) coupled to the wet contact, to protect the wet contact fromarcing during the make and break transitions and to reduce deleteriouseffects from contact arcing. The arc suppressor incorporated with thepower contact health assessor discussed herein may include an arcsuppressor as disclosed in the following issued U.S. patents—U.S. Pat.Nos. 8,619,395 and 9,423,442, both of which are incorporated herein byreference in their entirety. A power contact arc suppressor extends theelectrical life of a power contact under any rated load into themechanical life expectancy range. Even though the figures depict a powercontact health assessor 1 with an internal arc suppressor, thedisclosure is not limited in this regard and the power contact healthassessor 1 may also use an external arc suppressor or no arc suppressor.

When a power contact can no longer break the electrode micro weld intime, the contact is considered failed. Anecdotally, the power relayindustry considers a contactor or relay contact failed if the contactstick duration exceeds one (1) second. The inevitable EoL event for anyrelay and contactor is a failure. Power contact EoL may be understood asthe moment when a relay/contactor fails either electrically ormechanically. Power relays and contactors power contacts either failclosed, open or somewhere in between. Published power contact releasetimes in relay and contactor datasheets are not the same as the powercontact stick duration. The relay industry considers contacts with acurrent carrying capability of 2 A or greater, power contacts. Contactswith a current carrying capability of less than 2 A may not beconsidered power contacts. Conventional techniques to determine powercontact condition may involve measuring power contact resistance. Suchmeasurements, however, are performed ex-situ, using complex andexpensive equipment to perform measurements.

Power contact electrode surface degradation/decay is associated withever increasing power contact stick durations. Techniques disclosedherein may be used to perform power contact health assessment for apower contact using in-situ, real-time, stand-alone operation by, e.g.,monitoring contact stick durations providing a contact health assessmentbased on the measured stick duration. In-situ may be understood toinvolve operating in an actual, real-life, application while operatingunder normal or abnormal conditions. Real-time may be understood toinvolve performance data that is actual and available at the time ofmeasurement. For example, real-time contact separation detection may beperformed using real-time voltage measurements of the power contactvoltage. Stand-alone-operation requires no additional connections,devices, or manipulations other than those outlined in the presentdisclosure this document (e.g., the main power connection, a relay coildriver connection, and an auxiliary power source connection).

FIG. 1 is a diagram of a system 100 including a power contact healthassessor, according to some embodiments. Referring to FIG. 1, the system100 may include a power contact health assessor 1 coupled to anauxiliary power source 2, a relay coil driver 3, a main power source 4,a dry relay 5, a wet relay 6, a main power load 7, and a datacommunication interface 19.

The dry relay 5 may include a dry relay coil coupled to dry relaycontacts, and the wet relay 6 may include a wet relay coil coupled towet relay contacts. The dry relay 5 may be coupled to the main powersource 4 via the power contact health assessor 1. The dry relay 5 may becoupled in series with the wet relay 6, and the wet relay 6 may becoupled to the main power load 7 via the power contact health assessor1. Additionally, the wet relay 6 may be protected by an arc suppressorcoupled across the wet relay contacts of the wet relay 6 (e.g., asillustrated in FIG. 2). Without an arc suppressor connected, the wetcontactor or relay 6 contacts may become sacrificial and the drycontactor or relay 5 contacts may remain in excellent condition duringnormal operation of the power contact health assessor 1, ensuring thatthe device clears a fault condition in the case where the wet relaycontacts have failed.

The main power source 4 may be an AC power source or a DC power source.Sources four AC power may include generators, alternators, transformers,and the like. Source four AC power may be sinusoidal, non-sinusoidal, orphase controlled. An AC power source may be utilized on a power grid(e.g., utility power, power stations, transmission lines, etc.) as wellas off the grid, such as for rail power. Sources for DC power mayinclude various types of power storage, such as batteries, solar cells,fuel cells, capacitor banks, and thermopiles, dynamos, and powersupplies. DC power types may include direct, pulsating, variable, andalternating (which may include superimposed AC, full wave rectification,and half wave rectification). DC power may be associated withself-propelled applications, i.e., articles that drive, fly, swim,crawl, dive, internal, dig, cut, etc. Even though FIG. 1 illustrates themain power source 4 as externally provided, the disclosure is notlimited in this regard and the main power source may be providedinternally, e.g., a battery or another power source. Additionally, themain power source 4 may be a single-phase or a multi-phase power source.

Even though FIG. 1 illustrates the power contact health assessor 1coupled to a dry relay 5 and a wet relay 6 that include a relay coil andrelay contacts, the disclosure is not limited in this regard and othertypes of interlock arrangements may be used as well, such as switches,contactors, or other types of interlocks. In some aspects, a contactormay be a specific, heavy duty, high current, embodiment of a relay.Additionally, the power contact health assessor 1 may be used togenerate an EoL prediction for a single power contact (one of thecontacts of relays 5 and 6) or multiple power contacts (contacts forboth relays 5 and 6).

The dry and wet contacts associated with the dry and wet relays in FIG.1 may each include a pair of contacts, such as electrodes. In someaspects, the main power load 7 may be a general-purpose load, such asconsumer lighting, computing devices, data transfer switches, etc. Insome aspects, the main power load 7 may be a resistive load, such as aresistor, heater, electroplating device, etc. In some aspects, the mainpower load 7 may be a capacitive load, such as a capacitor, capacitorbank, power supply, etc. In some aspects, the main power load 7 may bean inductive load, such as an inductor, transformer, solenoid, etc. Insome aspects, the main power load 7 may be a motor load, such as amotor, compressor, fan, etc. In some aspects, the main power load 7 maybe a tungsten load, such as a tungsten lamp, infrared heater, industriallight, etc. In some aspects, the main power load 7 may be a ballastload, such as a fluorescent light, a neon light, a light emitting diode(LED), etc. In some aspects, the main power load 7 may be a pilot dutyload, such as a traffic light, signal beacon, control circuit, etc.

The auxiliary power source 2 is an external power source that providespower to the wet and dry relay coils (of the wet relay 6 and the dryrelay 5, respectively) according to the power contact health assessor 1.The first auxiliary power source node 21 may be configured as a firstcoil power termination input (e.g., to the auxiliary power terminationand protection circuit 12 in FIG. 2). The second auxiliary power sourcenode 22 may be configured as the second coil power termination input.The auxiliary power source 2 may be a single-phase or a multi-phasepower source. Additionally, the coil power source 2 may be an AC powertype or a DC power type.

The relay coil driver 3 is the external relay coil signal source whichprovides information about the energization status for the wet relay 6coil and the dry relay 5 coil according to the control of the powercontact health assessor 1. In this regard, the relay coil driver 3 isconfigured to provide a control signal. The first relay coil driver node31 is a first coil driver termination input (e.g., to relay coiltermination and protection circuit 14 in FIG. 2). The second relay coildriver node 32 may be configured as the second coil driver terminationinput. The relay coil driver 3 may be a single-phase or a multi-phasepower source. Additionally, the relay coil driver 3 may be an AC powertype or a DC power type.

The data communication interface 19 is an optional element that iscoupled to the power contact health assessor 1 via one or morecommunication links 182. The data communication interface 19 may becoupled to external memory and may be used for, e.g., storing andretrieving data.

Data communication may not be required for the full functional operationof the power contact health assessor 1. In some aspects, the datacommunication interface 19 can include one or more of the followingelements: a digital signal isolator, an internal transmit data (T×D)termination, an internal receive data (R×D) termination, an externalreceive data (Ext R×D) termination, and an external transmit data (ExtT×D) termination.

Data signal filtering, transient, over-voltage, over-current, and wiretermination are not shown in the example data communication interface 19in FIG. 1 and FIG. 2. In some aspects, the data communications interface19 can be configured as an interface between the power contact healthassessor 1 and one or more of the following: a Bluetooth controller, anEthernet controller, a General Purpose Data Interface, aHuman-Machine-Interface, an SPI bus interface, a UART interface, a USBcontroller, and a Wi-Fi controller.

The dry relay 5 may include two sections—a dry relay coil and dry relaycontacts. As mentioned above, “dry” refers to the specific mode ofoperation of the contacts in this relay which makes or breaks thecurrent connection between the contacts while not carrying current.

The first dry relay node 51 is the first dry relay 5 coil input from thepower contact health assessor 1. The second dry relay node 52 is thesecond dry relay 5 coil input from the power contact health assessor 1.The third dry relay node 53 is the first dry relay contact connectionwith the main power source 4. The fourth dry relay node 56 is the seconddry relay contact connection (e.g., with the wet relay 6). The dry relay5 may be configured to operate with a single-phase or a multi-phasepower source. Additionally, the dry relay 5 may be an AC power type or aDC power type.

The wet relay 6 may include two sections—a wet relay coil and wet relaycontacts. As mentioned above, “wet” refers to the specific mode ofoperation of the contacts in this relay which makes or breaks thecurrent connection between the contacts while carrying current.

The first wet relay node 61 is the first wet relay 6 coil input from thepower contact health assessor 1. The second wet relay node 62 is thesecond wet relay 6 coil input from the power contact health assessor 1.The third wet relay node 63 is the first wet relay contact connection(e.g., with the dry relay). The fourth wet relay node 66 is the secondwet relay contact connection (e.g., with the current sensor 127). Thewet relay 6 may be configured to operate with a single-phase or amulti-phase power source. Additionally, the wet relay 6 may be an ACpower type or a DC power type.

In some aspects, the power contact health assessor 1 is configured tosupport both the normally open (NO) contacts (also referred to as Form Acontacts) and the normally closed (NC) contacts (also referred to asForm B contacts). In some aspects, the power contact health assessor 1measures, records, and analyzes the time difference between coilactivation (or deactivation) and power contact activation (ordeactivation). In this regard, by monitoring and measuring contact stickdurations (e.g., for multiple contact cycles), the gradual power contactelectrode surface degradation/decay/decay may be detected and theestimated EoL may be predicted in absolute or relative terms for thepower contact. For example, the power contact EoL prediction may beexpressed in percent of cycles left to EoL, numbers of cycles, etc.

In some aspects, the power contact health assessor 1 contains elementsof a wet/dry power contact sequencer. In some aspects, the power contacthealth assessor 1 contains elements of a power contact fault clearingdevice. In some aspects, the power contact health assessor 1 containselements of a power contact End-of-Life predictor. In some aspects, thepower contact health assessor 1 contains elements of a power contactelectrode surface plasma therapy device. In some aspects, the powercontact health assessor 1 contains elements of an arc suppressor (thearc suppressor may be an optional element of the power contact healthassessor 1).

The discussed specific power contact health assessor operations may bebased on instructions located either in internal or externalmicrocontroller/processor memory. In some aspects, wet/dry power contactsequencing operations may operate in support of the power contact healthassessor 1. In some aspects, power contact fault clearing operations mayoperate in support of the power contact health assessor 1. In someaspects, power contact End-of-Life predictor operations may operate insupport of the power contact health assessor 1. In some aspects, powercontact electrode surface plasma therapy operation may operate insupport of the power contact health assessor 1. The power contact healthassessment operations discussed herein may be performed in-situ and inreal time, while the contact is performing under regular or abnormaloperating conditions. In some aspects, contact maintenance schedules maybe based on the actual health conditions of under power operatingcontacts, as determined one or more of the techniques discussed herein.

Power contact electrodes are micro welded during the make and especiallyduring the make bounce phase of the current carrying contact cycle.Micro welds between contact electrodes are desired for they provide thelow contact resistance required for power current conducting. Contactstick duration analysis in the power contact health assessor 1 is ameasure of contact performance degradation due to adverse contactconditions due to erosion in the form of and contact electrode surfacedecomposition. The contact stick duration is the difference between themoment the relay coil driver power de-activates and the power contactseparates.

In some aspects, stick duration=time of contact opening−time of coilde-activation. Stick durations are typically measured in milliseconds.Contact stick durations are an indication of contact conditions health(contact stick durations getting longer over time are indications ofdecaying contact health). Long contact stick durations are an indicationof poor contact health. When contact sticking becomes permanent, thenthe contact has failed. Contact stick durations over 1 second aregenerally considered a contact failure in the relay industry. In someaspects, stop time to arc minus the start time of the coil signaltransition is equivalent to the contact stick duration.

In some aspects, separation of contact detection allows for apredictable timing reference in order to determine the time differencebetween coil deactivation Form A and the opening of the contact. Thistime difference is greatly influenced by the duration of contactsticking due to normal contact micro welding. Even if the break of themicro weld takes more than one second, the contact may still prove to befunctional albeit passed normal expectations. Once the micro weld cannotbe broken anymore by the force of the contactor mechanism which isdesigned to open the contact or break the micro weld, the contact may beconsidered failed. In some aspects, contact sticking is the timedifference between the coil activation signal to break the contact andthe actual contact separation. In this regard, contact sticking may anindication of contact failure and not necessarily an increase in contactresistance.

The power contact health assessor discussed herein may be associatedwith the following features and benefits: AC or DC coil power andcontact operation; authenticity and license control mechanisms; autodetect functions; auto generate service and maintenance calls; auto modesettings; automatic fault detection; automatic power failure coil signalbypass; assessing power contact electrode surface decomposition degree;assessing power contact electrode surface decay; assessing power contactelectrode surface decay acceleration; assessing power contact electrodesurface decay deceleration; assessing power contact electrode surfacedecomposition degree; assessing power contact electrode surface healthcondition; assessing power contact electrode surface performance level;bar graph indicator; behavior pattern learning resulting inout-of-pattern detection and indication; cell phone application; codeverification chip; conducting real time power contact health diagnosis;conducting in-situ power contact health diagnosis; diagnosing powercontact health symptoms; EMC compliance; enabling off-sitetroubleshooting; enabling faster cycle times; enabling lower dutycycles; enabling heavy duty operation with lighter duty contactors orrelays; enabling high dielectric operation; enabling high poweroperation; enabling low leakage operation; enabling relays to replacecontactors; external and internal contactors or relays; hybrid powerrelays, contactors and circuit breakers; intelligenthybrid-power-switching controllers; internet appliances; local andremote data access; local and remote firmware upgrades; local and remoteregister access; local and remote system diagnostics; local and remotetroubleshooting; maximizing power contact life; maximizing equipmentlife; maximizing productivity; minimizing planned maintenance schedules;minimizing unplanned service calls; minimizing down times; minimizingproduction outages; mode control selection; multi-phase configuration;on-site or off-site troubleshooting; operating mode indication; powerindication; processor status indication color codes; single-phaseconfiguration; supporting high dielectric isolation between power sourceand power load; supporting low leakage current between power source andpower load; and trigger automatic service calls.

In some aspects, the power contact health assessor 1 may use thefollowing data communication interfaces: access control, Bluetoothinterface, communication interfaces and protocols, encrypted datatransmissions, an Ethernet interface, LAN/WAN connectivity, SPI businterface, UART, a universal data interface, a USB interface, and aWi-Fi interface.

In some aspects, the power contact health assessor 1 may use thefollowing power contact parameters and interfaces: power contact arccurrent, power contact arc duration, power contact arc type, powercontact arc voltage, power contact break bounce parameters, powercontact break bounce duration, power contact current, power contactcycle counts, power contact cycle duration, power contact cyclefrequency, power contact cycle times, power contact duty cycle, powercontact energy, power contact fault and failure alerts and alarms, powercontact fault and failure code clearing, power contact fault and failuredetection, power contact fault and failure flash codes, power contactfault and failure history and statistics, power contact fault andfailure alert, power contact fault and failure parameters, power contacthealth, power contact history, power contact hours-of-service, powercontact make bounce parameters, power contact make bounce duration,power contact on duration, power contact off duration, power contactpower, power contact resistance, power contact stick duration (PCSD),power contact average stick duration (PCASD), power contact peak stickduration (PCPSD), power contact stick duration crest factor (PCSDCF),power contact stick parameters, power contact parameter history, powercontact parameter statistics, power contact statistics, power contactstatus, power contact voltage, and power contact voltage crest factor.

The power contact health assessor 1 or may be associated with thefollowing results and the following beneficial outcomes: reducing oreliminating preventive maintenance program requirements; reducing oreliminating scheduled service calls; reducing or eliminatingprophylactic contact, relay or contactor replacements; and power contactlife degradation/decay detection. Data communication interfacing may beoptional for the discussed health assessor.

In comparison, conventional techniques are based on ex-situ analysis ofpower contact resistance increase as an indication of power contactdecay and a metric for impending power contact failure prediction. Suchconventional techniques are not based on in-situ health assessment, notbased on mathematical analysis, and not taking into account the instantof power contact separation.

FIG. 2 is a block diagram of an example power contact health assessor 1with an arc suppressor, according to some embodiments. Referring to FIG.2, the power contact health assessor 1 comprises an auxiliary powertermination and protection circuit 12, a relay coil termination andprotection circuit 14, a logic power supply 15, a coil signal converter16, mode control switches 17, a controller (also referred to asmicrocontroller or microprocessor) 18, data communication interface 19,a status indicator 110, a code control chip 120, a voltage sensor 123,an overcurrent protection circuit 124, a voltage sensor 125, an arcsuppressor 126 (e.g., with a contact separation detector (CSD)), acurrent sensor 127, a dry coil power switch 111, a dry coil currentsensor 113, a wet coil power switch 112, and a wet coil current sensor114.

The auxiliary power termination and protection circuit 12 is configuredto provide external wire termination and protection to all elements ofthe power contact health assessor 1. The first auxiliary powertermination and protection circuit 12 node 121 is the first logic powersupply 15 input, the first coil power switch 111 input, and the firstcoil power switch 112 input. The second auxiliary power termination andprotection circuit 12 node 122 is the second logic power supply 15input, the second coil power switch 111 input, and the second coil powerswitch 112 input.

In some aspects, the auxiliary power termination and protection circuit12 is includes one or more of the following elements: a first relay coildriver terminal, a second relay coil driver terminal, an overvoltageprotection, an overcurrent protection, a reverse polarity protection,optional transient and noise filtering, optional current sensor, andoptional voltage sensor.

The relay coil termination and protection circuit 14 provides externalwire termination and protection to all elements of the power contacthealth assessor 1. The first coil termination and protection circuit 14node 141 is the first coil signal converter circuit 16 input. The secondcoil termination and protection circuit 14 node 142 is the second coilsignal converter 16 input.

In some aspects, the relay coil termination and protection circuit 14includes one or more of the following elements: a first relay coildriver terminal, a second relay coil driver terminal, an overvoltageprotection, an overcurrent protection, a reverse polarity protection,optional transient and noise filtering, a current sensor (optional), anda voltage sensor (optional).

The logic power supply 15 is configured to provide logic level voltageto all digital logic elements of the power contact health assessor 1.The first logic power supply output 151 is the positive power supplyterminal indicated by the positive power schematic symbol in FIG. 2. Thesecond logic power supply output 152 is the negative power supplyterminal indicated by the ground reference symbol in FIG. 2.

In some aspects, the logic power supply 15 includes one or more of thefollowing elements: an AC-to-DC converter, input noise filtering, andtransient protection, input bulk energy storage, output bulk energystorage, output noise filtering, a DC-to-DC converter (alternative), anexternal power converter (alternative), a dielectric isolation (internalor external), an overvoltage protection (internal or external), anovercurrent protection (internal or external), product safetycertifications (internal or external), and electromagnetic compatibilitycertifications (internal or external).

The coil signal converter circuit 16 converts a signal indicative of theenergization status of the wet and dry coils from the relay coil driver3 into a logic level type signal communicated to the controller 18 vianode 187 for further processing.

In some aspects, the coil signal converter 16 is comprised of one ormore of the following elements: current limiting elements, dielectricisolation, signal indication, signal rectification, optional signalfiltering, optional signal shaping, and optional transient and noisefiltering.

The mode control switches 17 allow manual selection of specific modes ofoperation for the power contact health assessor 1. In some aspects, themode control switches 17 include one or more of the following elements:push buttons for hard resets, clearings or acknowledgements, DIPswitches for setting specific modes of operation, and (alternatively inplace of push buttons) keypad or keyboard switches.

The controller 18 comprises suitable circuitry, logic, interfaces,and/or code and is configured to control the operation of the powercontact health assessor 1 through, e.g., software/firmware-basedoperations, routines, and programs. The first controller node 181 is thestatus indicator 110 connection. The second controller node 182 is thedata communication interface 19 connection. The third controller node183 is the dry coil power switch 111 connection. The fourth controllernode 184 is the wet coil power switch 112 connection. The fifthcontroller node 185 is the dry coil current sensor 113 connection. Thesixth controller node 186 is the wet coil current sensor 114 connection.The seventh controller node 187 is the coil signal converter circuit 16connection. The eight controller node 188 is the code control chip 120connection. The ninth controller node 189 is the mode control switches17 connection. The tenth controller node 1810 is the overcurrent voltagesensor 123 connection. The eleventh controller node 1811 is the voltagesensor 125 connection. The twelfth controller node 1812 is the arcsuppressor 126 lock connection. The thirteenth controller node 1813 isthe first current sensor 127 connection. The fourteenth controller node1814 is the second current sensor 127 connection.

In some aspects, controller 18 may be configured to control one or moreof the following operations associated with the power contact healthassessor 1: algorithm management; authenticity code control management;auto-detect operations; auto-detect functions; automatic normally closedor normally open contact form detection; auto mode settings; coil cycle(Off, Make, On, Break, Off) timing, history, and statistics; coil delaymanagement; history management; power contact sequencing; coil driversignal chatter history and statistics; data management (e.g.,monitoring, detecting, recording, logging, indicating, and processing);data value registers for present, last, past, maximum, minimum, mean,average, standard deviation values, etc.; date and time formatting,logging, and recording; embedded microcontroller with clock generation,power on reset, and watchdog timer; error, fault, and failuremanagement; factory default value recovery management; firmware upgrademanagement; flash code generation; fault indication clearing; faultregister reset; hard reset; interrupt management; license code controlmanagement; power-on management; power-up sequencing; power hold-overmanagement; power turn-on management; reading from inputs, memory, orregisters; register address organization; register data factory defaultvalues; register data value addresses; register map organization; softreset management; SPI bus link management; statistics management; systemaccess management; system diagnostics management; UART communicationslink management; wet/dry relay coil management; and writing to memory,outputs, and registers.

The status indicator 110 provides audible, visual, or other useralerting methods through operational, health, fault, code indication viaspecific colors or flash patterns. In some aspects, the status indicator110 may provide one or more of the following types of indications: bargraphs, graphic display, LEDs, a coil driver fault indication, a coilstate indication, a dry coil fault indication, a mode of operationindication, a processor health indication, and wet coil faultindication.

The dry coil power switch 111 connects the externally provided coilpower to the dry relay coil 5 via nodes 51 and 52 based on the signaloutput from controller 18 via command output node 183. In some aspects,the dry coil power switch 111 includes one or more of the followingelements: solid-state relays, current limiting elements, and optionalelectromechanical relays.

The wet coil power switch 112 connects the externally provided coilpower to the wet relay coil 6 via nodes 61 and 62 based on the signaloutput from controller 18 via command output node 184. In some aspects,the wet coil power switch 112 includes one or more of the followingelements: solid-state relays, current limiting elements, and optionalelectromechanical relays.

The dry coil current sensor 113 is configured to sense the value and/orthe absence or presence of the dry relay coil 5 current. In someaspects, the dry coil current sensor 113 includes one or more of thefollowing elements: solid-state relays, a reverse polarity protectionelement, optoisolators, optocouplers, Reed relays and/or Hall effectsensors (optional), SSR AC or DC input (alternative), and SSR AC or DCoutput (alternative).

The wet coil current sensor 114 is configured to sense the value and/orthe absence or presence of the dry relay coil 6 current. In someaspects, the wet coil current sensor 114 includes one or more of thefollowing elements: solid-state relays, a reverse polarity protectionelement, optoisolators, optocouplers, Reed relays and/or Hall effectsensors (optional), SSR AC or DC input (alternative), and SSR AC or DCoutput (alternative).

The code control chip 120 is an optional element of the power contacthealth assessor 1, and it is not required for the fully functionaloperation of the device. In some aspects, the code control chip 120 maybe configured to include application or customer specific code withencrypted or non-encrypted data security. In some aspects, the codecontrol chip 120 function may be implemented externally via the datacommunication interface 19. In some aspects, the code control chip 120may be configured to store the following information: access controlcode and data, alert control code and data, authentication control codeand data, encryption control code and data, chip control code and data,license control code and data, validation control code and data, and/orchecksum control code and data. In some aspects, the code control chip120 may be implemented as an internal component of controller 18 or maybe a separate circuit that is external to controller 18 (e.g., asillustrated in FIG. 2).

The voltage sensor 123 is configured to monitor the condition of theovercurrent protection 124. In some aspects, the voltage sensor 123includes one or more of the following elements: solid-state relays, abridge rectifier, current limiters, resistors, capacitors, reversepolarity protection elements, optoisolators, optocouplers, Reed relaysand analog to digital converters (optional).

The overcurrent protection circuit 124 is configured to protect thepower contact health assessor 1 from destruction in case of anovercurrent condition. In some aspects, the overcurrent protectioncircuit 124 includes one of more of the following elements: fusibleelements, fusible printed circuit board traces, fuses, and circuitbreakers.

The voltage sensor 125 is configured to monitor the voltage across thewet relay 6 contacts. In some aspects, the voltage sensor 125 includesone or more of the following elements: solid-state relays, a bridgerectifier, current limiters, resistors, capacitors, reverse polarityprotection elements, and alternative or optional elements such asoptoisolators, optocouplers, solid-state relays, Reed relays, andanalog-to-digital converters. In some aspects, the voltage sensor 125may be used for detecting contact separation of the contact electrodesof the wet relay 6. More specifically, the connection 1811 may be usedby the controller 18 to detect that a voltage between the contactelectrodes of the wet relay 6 measured by the voltage sensor 125 is at aplasma ignition voltage level (or arc initiation voltage level) orabove. The controller 18 may determine there is contact separation ofthe contact electrodes of the wet relay 6 when such voltage levels arereached or exceeded. The determined time of contact separation may beused to determine contact stick duration, which may be used for thepower contact health assessment.

The arc suppressor 126 is configured to provide arc suppression for thewet relay 6 contacts. The arc suppressor 126 may be either external tothe power contact health assessor 1 or, alternatively, may beimplemented as an integrated part of the power contact health assessor1. The arc suppressor 126 may be configured to operate with asingle-phase or a multi-phase power source. Additionally, the arcsuppressor 8 may be an AC power type or a DC power type.

In some aspects, the arc suppressor 126 may be deployed for normal loadconditions. In some aspects, the arc suppressor 126 may or may not bedesigned to suppress a contact fault arc in an overcurrent or contactoverload condition.

In some aspects, the connection 1812 between the arc suppressor 126 lockand the controller 18 may be used for enabling (unlocking) the arcsuppressor (e.g., when the relay coil driver signal is active) ordisabling (locking) the arc suppressor (e.g., when the relay coil driversignal is inactive).

In some aspects, the arc suppressor 126 may include a contact separationdetector (CSD) (not illustrated in FIG. 2) configured to detect a timeinstance when the wet relay 6 power contact electrodes separate as partof a contact cycle. A connection with the controller 18 (e.g., 1812) maybe used to communicate a contact separation indication of a timeinstance when the CSD has detected contact separation within a contactcycle of the wet relay 6. The contact separation indication may be usedby the controller 18 to provide a power contact health assessment withregard to the condition of the contact electrodes of the wet relay 6.

In some aspects, the arc suppressor 126 may be a single-phase or amulti-phase arc suppressor. Additionally, the arc suppressor may be anAC power type or a DC power type.

The current sensor 127 is configured to monitors the current through thewet relay 6 contacts. In some aspects, the current sensor 126 includesone of more of the following elements: solid-state relays, a bridgerectifier, current limiters, resistors, capacitors, reverse polarityprotection elements, and alternative or optional elements such asoptoisolators, optocouplers, Reed relays, and analog-to-digitalconverters.

In some aspects, the controller 18 status indicator output pin (SIO) pin181 transmits the logic state to the status indicators 110. SIO is thelogic label state when the status indicator output is high, and /SIO isthe logic label state when the status indicator output is low.

In some aspects, the controller 18 data communication interfaceconnection (TXD/RXD) 182 transmits the data logic state to the datacommunications interface 19. RXD is the logic label state identifyingthe receive data communications mark, and /RXD is the logic label stateidentifying the receive data communications space. TXD is the logiclabel state identifying the transmit data communications mark, and /TXDis the logic label state identifying the transmit data communicationsspace.

In some aspects, the controller 18 dry coil output (DCO) pin 183transmits the logic state to the dry coil power switch 111. DCO is thelogic label state when the dry coil output is energized, and /DCO is thelogic label state when the dry coil output is de-energized.

In some aspects, the controller 18 wet coil output pin (WCO) 184transmits the logic state to the wet coil power switch 112. WCO is thelogic state when the wet coil output is energized, and /WCO is the logicstate when the wet coil output is de-energized.

In some aspects, the controller 18 dry coil input pin (DCI) 185 receivesthe logic state of the dry coil current sensor 113. DCI is the logicstate when the dry coil current is absent, and /DCI is the logic statewhen the dry coil current is present.

In some aspects, the controller 18 wet coil input pin (WCI) 186 receivesthe logic state of the wet coil current sensor 114. WCI is the logiclabel state when the wet coil current is absent, and /WCI is the logiclabel state when the wet coil current is present.

In some aspects, the controller 18 coil driver input pin (CDI) 187receives the logic state of the coil signal converter 16. CDI is thelogic state of the de-energized coil driver. /CDI is the logic state ofthe energized coil driver.

In some aspects, the controller 18 code control connection (CCC) 188receives and transmits the logic state of the code control chip 120. CCRis the logic label state identifying the receive data logic high, and/CCR is the logic label state identifying the receive data logic low.CCT is the logic label state identifying the transmit data logic high,and /CCT is the logic label state identifying the transmit data logiclow.

In some aspects, the controller 18 mode control switch input pin (S) 189receives the logic state from the mode control switches 17. S representsthe mode control switch open logic state, and /S represents the modecontrol switch closed logic state.

In some aspects, the controller 18 connection 1810 receives the logicstate from the overcurrent protection (OCP) voltage sensor 123. OCPVS isthe logic label state when the OCP is not fused open, and /OCPVS is thelogic label state when the OCP is fused open.

In some aspects, the controller 18 connection 1811 receives the logicstate from the wet contact voltage sensor (VS) 125. WCVS is the logiclabel state when the VS is transmitting logic high, and /WCVS is thelogic label state when the VS is transmitting logic low.

In some aspects, the controller 18 connection 1812 transmits the logicstate to the arc suppressor 126 lock. ASL is the logic label state whenthe arc suppression is locked, and /ASL is the logic label state whenthe arc suppression is unlocked.

In some aspects, the controller 18 connections 1813 and 1814 receive thelogic state from the contact current sensor 127. CCS is the logic labelstate when the contact current is absent, and /CCS is the logic labelstate when the contact current is present.

In some aspects, the controller 18 may configure one or more timers(e.g., in connection with detecting a fault condition and sequencing thedeactivation of the wet and dry contacts). Example timer labels anddefinitions of different timers that may be configured by controller 18include one or more of the following timers.

In some aspects, the coil driver input delay timer delays the processingfor the logic state of the coil driver input signal.COIL_DRIVER_INPUT_DELAY_TIMER is the label when the timer is running.

In some aspects, the switch debounce timer delays the processing for thelogic state of the switch input signal. SWITCH_DEBOUNCE_TIMER is thelabel when the timer is running.

In some aspects, the receive data timer delays the processing for thelogic state of the receive data input signal. RECEIVE_DATA_DELAY_TIMERis the label when the timer is running.

In some aspects, the transmit data timer delays the processing for thelogic state of the transmit data output signal.TRANSMIT_DATA_DELAY_TIMER is the label when the timer is running.

In some aspects, the wet coil output timer delays the processing for thelogic state of the wet coil output signal. WET_COIL_OUTPUT_DELAY_TIMERis the label when the timer is running.

In some aspects, the wet current input timer delays the processing forthe logic state of the wet current input signal.WET_CURRENT_INPUT_DELAY_TIMER is the label when the timer is running.

In some aspects, the dry coil output timer delays the processing for thelogic state of the dry coil output signal. DRY_COIL_OUTPUT_DELAY_TIMERis the label when the timer is running.

In some aspects, the dry current input timer delays the processing forthe logic state of the dry current input signal.DRY_CURRENT_INPUT_DELAY_TIMER is the label when the timer is running.

In some aspects, the signal indicator output delay timer delays theprocessing for the logic state of the signal indicator output.SIGNAL_INDICATOR_OUTPUT_DELAY_TIMER is the label when the timer isrunning.

Contact Stick Duration

The power contact stick duration, its growth, and its change of growthas a function of the number of contact cycles within a series ofconsecutive observation windows and their mathematical analysis aresurrogates for the electrode surface degradation/decay and are the basisfor power contact health assessment. As mentioned above, the powercontact stick duration is the time difference between the coilactivation signal to break the power contact and the actual powercontact separation.

In some aspects, the power CSD (e.g., located inside the arc suppressor126 or as a separate circuit) reports the precise moment of contactseparation. This is the very moment the contact breaks the micro weldand the two contact electrodes start to move away from each other.Without an arc suppressor, even though the contact is separated, and theelectrodes are moving away from each other, due to the maintained arcbetween the two electrodes, current is still flowing across the contactand through the power load. The power CSD provides a higher degree ofprediction accuracy compared to using the moment where the current stopsflowing between the separating power contact electrodes when themaintained arc terminates.

In some aspects, analysis of power contact stick duration over time, asthe contact keeps on power cycling through its operational life, allowsfor the power contact health assessment by the health assessor 1. Forexample, increasing power contact stick durations, as the number ofcontact cycles increases, is an indication of deteriorating powercontact health (e.g., surface electrode degradation/decay).

A certain power contact stick duration is considered by the relayindustry as a failure and a permanently welded contact is a failed powercontact. When a power contact gets older, the power contact stickduration becomes longer. When the spring force becomes weaker over timethen the power contact stick durations become longer. When the currentis higher and the micro weld gets stronger, the power contact stickdurations become longer. In some aspects, mathematical analysis of powercontact stick duration as a function of power contact cycles allows forpower contact health assessment. The mathematical analysis compares thepower contact stick duration increase between two fixed, non-overlappingsampling windows. Power contact stick duration increase is also anindication of power contact decay and a surrogate for impending powercontact failure prediction.

In some aspects, contact sticking (e.g., for normally open NO (Form A)contacts) may be measured as the coil de-energizing event starts theduration timer and the contact load current break arc (or the moment ofcontact separation) stops the timer.

A contactor is a specific, usually heavy duty, high current, embodimentof a relay. Experimental evidence while investigating power contactelectrode surface erosion has shown that the contact stick duration maybe used as a surrogate for the power contact health. Furtherinvestigation has shown that the power contact stick duration becomeslonger and longer as the total number of contact cycles in a powerapplication. The contact stick duration is made worst overtime due tothe increased and compounded power contact electrode surface erosion inthe form of asperities, craters, and pits. In this regard, while thepower contact stick duration increases, the power contact healthdecreases.

Yet further investigation has shown that the contact stick duration andcontact health relationship is neither linear nor following a naturalexponential decay law but an exponential decay law in the form ofA(N)=A(ref)*B{circumflex over ( )}N, where A(ref) is the first referencestick duration from a new condition power contact of a relay orcontactor, A(N) is the stick duration after N contact cycles, B is thestick duration growth factor, and N is the number of contact cycles.

In aspects when A(ref)=40 ms, the initial reference power contact stickduration A(N)=1000 ms, the industry accepted maximum power contact stickduration N=10,000,000 cycles (may be considered as a typical “maximumpower contact electrical life expectancy”). Therefore, B=321.87×10E-9.This value is an extremely low stick duration growth rate and may notagree with actual experienced maximum power contact electrical lifewhile operating at rated power loads. Some relay and contactormanufacturers publish load-dependent maximum electrical contact lifetables in their datasheets.

Due to inconsistencies and confusion relating to power contactelectrical life expectancies, the techniques discussed herein may beused for a power contact health assessor capable of measuring stickdurations, calculating, quantitatively and qualitatively assessing theactual health conditions of contacts in power relays and contactors. Insome aspects, power contact health assessments may be based on the ratioof power contact average stick durations between two or morewindows-of-observation (WoO).

FIG. 3 depicts a logarithmic scale graph 300 of average power contactstick duration for power contact health assessment, according to someembodiments.

In some aspects, the windows-of-observation may be established asfollows (and in reference to graph 300 in FIG. 3). After resetting thepower contact health assessor or clearing stick duration register, afirst window-of-observation (WoO1) may be set-up. The firstwindow-of-observation starts with the first power contact stick durationmeasurement and ends for example after the 100th stick durationmeasurement (e.g., N1=100 contact cycles). As seen in FIG. 3, the powercontact average stick duration for WoO1 is 31.25 ms.

Subsequent windows-of-observation may be configured based on the firstwindow and the average stick duration of the first window. The secondwindow-of-observation WoO2 starts with the 101^(st) measurement. Thesecond window-of-observation may be configured to end when the powercontact average stick duration is, e.g., twice (or another multiple) thevalue of the first window-of-observation average stick duration. In theexample in FIG. 3, WoO2 ends when the average stick duration for thatwindow reaches 2×31.25 ms=62.5 ms (at contact cycle N2, where N2 may bedifferent from N1).

The third window-of-observation (WoO3) starts after the secondwindow-of-observation (after the N2 contact cycles). The thirdwindow-of-observation ends when the power contact average stick durationis, e.g., twice (or another multiple) the value of the secondwindow-of-observation average stick duration. In the example in FIG. 3,WoO3 ends when the average stick duration for that window reaches 2×62.5ms=125 ms

The fourth window-of-observation (WoO4) starts after the thirdwindow-of-observation (after the N3 contact cycles). The fourthwindow-of-observation ends when the power contact average stick durationis, e.g., twice (or another multiple) the value of the thirdwindow-of-observation average stick duration. In the example in FIG. 3,WoO4 ends when the average stick duration for that window reaches 2×125ms=250 ms

The fifth window-of-observation (WoO5) starts after the fourthwindow-of-observation (after the N4 contact cycles). The fifthwindow-of-observation ends when the power contact average stick durationis, e.g., twice (or another multiple) the value of the fourthwindow-of-observation average stick duration. In the example in FIG. 3,WoO5 ends when the average stick duration for that window reaches 2×250ms=500 ms

The sixth window-of-observation (WoO6) starts after the fifthwindow-of-observation (after the N5 contact cycles). The sixthwindow-of-observation ends when the power contact average stick durationis, e.g., twice (or another multiple) the value of the fifthwindow-of-observation average stick duration. In the example in FIG. 3,WoO6 ends when the average stick duration for that window reaches 2×500ms=1000 ms.

In some aspects, the last window-of-observation (or observation window)is configured so that the average stick duration for that window equalsa pre-defined stick duration threshold value (e.g., 1000 ms which isconsidered an industry limit indicating a contact has failed). Each ofthe obtained/configured observation windows can be associated with acorresponding health assessment characteristic indicative of the healthof the contact electrodes when a contact stick duration for theelectrodes falls within the corresponding window. For example, if acontact stick duration is measured at any given moment as 100 ms, ahealth assessment of “average” may be output as 100 ms falls withinobservation window WoO3. In some aspects, percentage indications may beused for the health assessment or a bar indicator to provide the powercontact health assessment for each of the configured observationwindows.

In some aspects, power contact stick duration (PCSD) may be measured foreach and every contact break instant as follows: PCSD=Contact OpenTime−Coil De-energization Time. In some aspects, the contact open timemay not be the same as the load current turn-off time. The load currentturns off after the arc is extinguished. Arc burn durations may be up toabout one-half power cycle. Furthermore, the arc may re-ignite and keepburning in the following power half cycle. The contact open time is thetime when the power contact break arc ignites.

In some aspects, power contact peak stick duration (PCPSD) may bemeasured and used for power contact health assessment. PCPSD may bemeasured and recorded as the as the maximum power contact stick duration(PCSDmax) within the specific time window-of-observation (orPCPSD=PCSDmax).

In some aspects, power contact average stick duration (PCASD) may bemeasured and used for power contact health assessment. PCASD may becalculated for one or more specific windows-of-observation. PCASD mayequal the sum of all stick durations within a defined window of timedivided by the number of contact cycles within the specificwindow-of-observation.

In some aspects, the power contact stick duration crest factor (PCSDCF)may be measured and used for power contact health assessment. PCSDCF maybe calculated for one or more specific time windows of observation.PCSTCF may equal the peak stick duration divided by the average stickduration within the specific window-of-observation.

In some aspects, power contact health assessment may be displayed andreported quantitatively in absolute values or relative values, such asabsolute quantitatively power contact health conditions including powercontact peak stick durations between 0 and 1000 ms.

In some aspects, power contact stick duration crest factors may becalculated as follows for the observation windows in FIG. 3 and used forpower contact health assessment: PCSDCF between 128 and 32 for the 0 to31.25 ms average stick time window-of-observation respectively(“mint/new condition failure”); PCSDCF between 32 and 16 for the 31.25to 62.5 ms average stick time window-of-observation respectively (“goodcondition failure”); PCSDCF between 16 and 8 for the 62.5 to 125 msaverage stick time window-of-observation respectively (“averagecondition failure”); PCSDCF between 8 and 4 for the 125 to 250 msaverage stick time window-of-observation respectively (“poor conditionfailure”); PCSDCF between 4 and 2 for the 250 to 500 ms average sticktime window-of-observation respectively (“replace condition failure”);and PCSDCF between 2 and 1 for the 500 to 1000 ms average stick timewindow-of-observation respectively (“failed condition failure”).

In some aspects, the following quantitative power contact healthassessment may be provided: power contact health condition from 100% to97% (new); power contact health condition from 97% to 94% (new); powercontact health condition from 94% to 87.5% (average); power contacthealth condition from 87.5% to 75% (poor); power contact healthcondition from 75% to 50% (replace); and power contact health conditionfrom 50% to 0% (failed).

In some aspects, power contact health assessment may be displayed andreported qualitatively, as follows: “new” for power contact averagestick durations (PCASD) from 0 to 31.25 ms; “good” for power contactaverage stick durations (PCASD) from 31.25 and 62.5 ms; “average” forpower contact average stick durations (PCASD) from 62.5 to 125 ms;“poor” for power contact average stick durations (PCASD) from 125 to 250ms; “replace” for power contact average stick durations (PCASD) from 250to 500 ms; and “failed” for power contact average stick durations(PCASD) from 500 to 1000 ms.

In some aspects, the power contact health assessor 1 registers may belocated internally or externally to the controller 18. For example, thecode control chip 120 can be configured to store the power contacthealth assessor 1 registers that are described hereinbelow.

In some aspects, address and data may be written into or read back fromthe registers through a communication interface using either UART, SPIor any other processor communication method.

In some aspects, the registers may contain data for the followingoperations: calculating may be understood to involve performingmathematical operations; controlling may be understood to involveprocessing input data to produce desired output data; detecting may beunderstood to involve noticing or otherwise detecting a change in thesteady state; indicating may be understood to involve issuingnotifications to the users; logging may be understood to involveassociating dates, times, and events; measuring may be understood toinvolve acquiring data values about physical parameters; monitoring maybe understood to involve observing the steady states for changes;processing may be understood to involve performing controller orprocessor-tasks for one or more events; and recording may be understoodto involve writing and storing events of interest into mapped registers.

In some aspects, the power contact health assessor 1 registers maycontain data arrays, data bits, data bytes, data matrixes, datapointers, data ranges, and data values.

In some aspects, the power contact health assessor 1 registers may storecontrol data, default data, functional data, historical data,operational data, and statistical data. In some aspects, the powercontact health assessor 1 registers may include authenticationinformation, encryption information, processing information, productioninformation, security information, and verification information. In someaspects, the power contact health assessor 1 registers may be used inconnection with external control, external data processing, factory use,future use, internal control, internal data processing, and user tasks.

In some aspects, reading a specific register byte, bytes, or bits mayreset the value to zero (0).

The following are example registers that can be configured for the powercontact health assessor 1.

In some aspects, a mode register (illustrated in TABLE 1) may beconfigured to contain the data bits for the selected mode. The powercontact health assessor 1 may be pre-loaded with register defaultsettings. In the default mode, the power contact health assessor 1 mayoperate stand-alone and independently as instructed by the factorydefault settings.

In some aspects, the following Read and Write commands may be used inconnection with the mode register: Read @ 0x60, and Write @ 0x20.

TABLE 1 Mode Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0INDICATE_FAULTS 1 — — — — — — — & FAILURES None 0 — — — — — — —INDICATE_NONE — 1 — — — — — — None — 0 — — — — — — INDICATE_ALL — — 1 —— — — — None — — 0 — — — — — STOP_ON_FAILURE — — — 1 — — — — None — — —0 — — — — HALT_ON_FAULT — — — — 1 — — — None — — — — 0 — — — RESET — — —— — 1 — — None — — — — — 0 — — CLEAR — — — — — — 1 — None — — — — — — 0— DEFAULT — — — — — — — 1 None — — — — — — — 0

In some aspects, an alert register (illustrated in TABLE 2) may beconfigured to contain the data bits for the selected alert method.

In some aspects, the following Read and Write commands may be used inconnection with the alert register: Read @ 0x61, and Write @ 0x21.

TABLE 2 Alert Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0 VOICE 1 — — —— — — — None 0 — — — — — — — COMM — 1 — — — — — — None — 0 — — — — — —BUZZER — — 1 — — — — — None — — 0 — — — — — SPEAKER — — — 1 — — — — None— — — 0 — — — — RECORD — — — — 1 — — — None — — — — 0 — — — SOUND — — —— — 1 — — None — — — — — 0 — — DISPLAY — — — — — — 1 — None — — — — — —0 — LED — — — — — — — 1 None — — — — — — — 0

In some aspects, a code control register (illustrated in TABLE 3) may beconfigured to contain the data array pointers for the selected codetype.

In some aspects, the following Read and Write commands may be used inconnection with the code control register: Read @ 0x62, and Write @0x22.

TABLE 3 Code Control Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0CHECKSUM 1 — — — — — — — None 0 — — — — — — — VALIDATION — 1 — — — — — —None — 0 — — — — — — LICENSE — — 1 — — — — — None — — 0 — — — — — CHIP —— — 1 — — — — None — — — 0 — — — — ENCRYPT — — — — 1 — — — None — — — —0 — — — AUTHENTIC — — — — — 1 — — None — — — — — 0 — — ALERT — — — — — —1 — None — — — — — — 0 — ACCESS — — — — — — — 1 None — — — — — — — 0

In some aspects, a contact limits register (illustrated in TABLE 4) maybe configured to contain the data array pointers for the selectedcontact limit specification.

In some aspects, the following Read and Write commands may be used inconnection with the contact limits register: Read @ 0x63, and Write @0x23.

TABLE 4 Contact Limits Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0MAX_MECH_LIFE 1 — — — — — — — None 0 — — — — — — — MAX_ELEC_LIFE — 1 — —— — — — None — 0 — — — — — — MAX_CYCLES_PER_MINUTE — — 1 — — — — — None— — 0 — — — — — MAX_DUTY_CYCLE — — — 1 — — — — None — — — 0 — — — —MIN_DUTY_CYCLE — — — — 1 — — — None — — — — 0 — — — MIN_OFF_DURATION — —— — — 1 — — None — — — — — 0 — — MIN_ON_DURATION — — — — — — 1 — None —— — — — — 0 — MIN_CYCLE_TIME — — — — — — — 1 None — — — — — — — 0

In some aspects, a data communication register (illustrated in TABLE 5)may be configured to contain the data bits for the selected datacommunications method.

In some aspects, the following Read and Write commands may be used inconnection with the data communication register: Read @ 0x64; and Write@0x24.

TABLE 5 Data Comm Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0 PROTOCOL1 — — — — — — — None 0 — — — — — — — HMI — 1 — — — — — — None — 0 — — —— — — BLUETOOTH — — 1 — — — — — None — — 0 — — — — — ETHERNET — — — 1 —— — — None — — — 0 — — — — WIFI — — — — 1 — — — None — — — — 0 — — — USB— — — — — 1 — — None — — — — — 0 — — SPI — — — — — — 1 — None — — — — —— 0 — UART — — — — — — — 1 None — — — — — — — 0

In some aspects, a coil driver parameter register (illustrated in TABLE6) may be configured to contain the data array pointers for the selectedcoil driver parameter specification.

In some aspects, the following Read and Write commands may be used inconnection with the coil driver parameter register: Read @ 0x65, andWrite @0x25.

TABLE 6 Coil Driver Parameters Register BIT NUMBER FUNCTION 7 6 5 4 3 21 0 COIL_DRIVER_PATTERN 1 — — — — — — — None 0 — — — — — — —COIL_DRIVER_OFF_CHATTER — 1 — — — — — — None — 0 — — — — — —COIL_DRIVER_ON_CHATTER — — 1 — — — — — None — — 0 — — — — —COIL_DRIVER_FREQUENCY — — — 1 — — — — None — — — 0 — — — —COIL_DRIVER_CYCLE_TIME — — — — 1 — — — None — — — — 0 — — —COIL_DRIVER_DUTY_CYCLE — — — — — 1 — — None — — — — — 0 — —COIL_DRIVER_ON_DURATION — — — — — — 1 — None — — — — — — 0 —COIL_DRIVER_OFF_DURATION — — — — — — — 1 None — — — — — — — 0

In some aspects, a coil driver pattern register (illustrated in TABLE 7)may be configured to contain the data bits for the selected coil driverpattern condition.

In some aspects, the following Read and Write commands may be used inconnection with the coil driver pattern register: Read @ 0x66, and Write@ 0x26.

TABLE 7 Coil Driver Pattern Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0COIL_DRIVER_ 1 — — — — — — — PATTERN_AQUIRED None 0 — — — — — — —COIL_DRIVER_ — 1 — — — — — — PATTERN_DETECTED None — 0 — — — — — —COIL_DRIVER_ — — 1 — — — — — PATTERN_LEARNED None — — 0 — — — — —OUT_OF_COIL_ — — — 1 — — — — DRIVER_PATTERN None — — — 0 — — — —IN_COIL_DRIVER_PATTERN — — — — 1 — — — None — — — — 0 — — —NO_COIL_DRIVER_PATTERN — — — — — 1 — — None — — — — — 0 — — AQUIRE_COIL_— — — — — — 1 — DRIVER_PATTERN None — — — — — — 0 — IGNORE_COIL_ — — — —— — — 1 DRIVER_PATTERN None — — — — — — — 0

In some aspects, a dry coil output delay timer register (illustrated inTABLE 8) may be configured to contain the values for the dry delaytiming.

In some aspects, the following Read and Write commands may be used inconnection with the dry relay register: Read @ 0x67, and Write @ 0x27.

TABLE 8 Dry Coil Output Delay Time Register BIT NUMBER VALUE 7 6 5 4 3 21 0 Maximum: 2550 ms 1 1 1 1 1 1 1 1 Default: 100 ms 0 0 0 0 1 0 1 0Minimum: 0 ms 0 0 0 0 0 0 0 0

In some aspects, a fault register (illustrated in TABLE 9) may beconfigured to contain the data bits for the selected fault condition.

In some aspects, the following Read and Write commands may be used inconnection with the fault register: Read @ 0x68, and Write @ 0x28.

TABLE 9 Fault Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0 COMM_FAULT 1— — — — — — — None 0 — — — — — — — POWER_BROWN_OUT — 1 — — — — — — None— 0 — — — — — — WATCH_DOG_TIMER — — 1 — — — — — None — — 0 — — — — —POWER_FAULT — — — 1 — — — — None — — — 0 — — — — DEVICE_HEALTH — — — — 1— — — None — — — — 0 — — — COIL_DRIVER_FAULT — — — — — 1 — — None — — —— — 0 — — DRY_COIL_VAULT — — — — — — 1 — None — — — — — — 0 —WET_COIL_FAULT — — — — — — — 1 None — — — — — — — 0

In some aspects, a flash code register (illustrated in TABLE 10) may beconfigured to contain the data bits for the selected LED flash codecolors.

In some aspects, the following Read and Write commands may be used inconnection with the flash code register: Read @ 0x69, and Write @ 0x29.

TABLE 10 LED Flash Code Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0FLASH_CODE7 1 — — — — — — — None 0 — — — — — — — FLASH_CODE6 — 1 — — — —— — None — 0 — — — — — — FLASH_CODE5 — — 1 — — — — — None — — 0 — — — —— FLASH_CODE4 — — — 1 — — — — None — — — 0 — — — — FLASH_CODE3 — — — — 1— — — None — — — — 0 — — — FLASH_CODE2 — — — — — 1 — — None — — — — — 0— — FLASH_CODE1 — — — — — — 1 — None — — — — — — 0 — FLASH_CODE0 — — — —— — — 1 None — — — — — — — 0

In some aspects, a history register (illustrated in TABLE 11) may beconfigured to contain the data array pointers for the selected historyinformation.

In some aspects, the following Read and Write commands may be used inconnection with the history register: Read @ 0x6A, and Write @ 0x2A.

TABLE 11 History Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0 STATUS 1 —— — — — — — None 0 — — — — — — — STATE — 1 — — — — — — None — 0 — — — —— — MODE — — 1 — — — — — None — — 0 — — — — — FAULT — — — 1 — — — — None— — — 0 — — — — OUTPUT — — — — 1 — — — None — — — — 0 — — — INPUT — — —— — 1 — — None — — — — — 0 — — DRIVER — — — — — — 1 — None — — — — — — 0— MODE — — — — — — — 1 None — — — — — — — 0

In some aspects, an input register (illustrated in TABLE 12) may beconfigured to contain the data bits for the selected input status.

In some aspects, the following Read and Write commands may be used inconnection with the input register: Read @ 0x6B, and Write @ 0x2B.

TABLE 12 Input Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0 DCI 1 — — —— — — — None 0 — — — — — — — WCI — 1 — — — — — — None — — 0 — — — — —RXD — — 1 — — — — — None — — 0 — — — — — S2C — — — 1 — — — — None — — —0 — — — — S2B — — — — 1 — — — None — — — — 0 — — — S2A — — — — — 1 — —None — — — — — 0 — — S1 — — — — — — 1 — None — — — — — — 0 — CDI — — — —— — — 1 None — — — — — — — 0

In some aspects, an LED color register (illustrated in TABLE 13) may beconfigured to contain the data bits for the selected LED color.

In some aspects, the following Read and Write commands may be used inconnection with the LED color register: Read @ 0x6C, and Write @ 0x2C.

TABLE 13 LED Color Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0 RED 1 —— — — — — — None 0 — — — — — — — RED_ORANGE — 1 — — — — — — None — 0 — —— — — — ORANGE_YELLOW — — 1 — — — — — None — — 0 — — — — — ORANGE — — —1 — — — — None — — — 0 — — — — YELLOW — — — — 1 — — — None — — — — 0 — —— YELLOW_GREEN — — — — — 1 — — None — — — — — 0 — — GREEN_YELLOW — — — —— — 1 — None — — — — — — 0 — GREEN — — — — — — — 1 None — — — — — — — 0

In some aspects, an output register (illustrated in TABLE 14) may beconfigured to contain the data bit for the selected output status.

In some aspects, the following Read and Write commands may be used inconnection with the output register: Read @ 0x6D, and Write @ 0x2D.

TABLE 14 Output Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0WET_COIL_OUTPUT 1 — — — — — — — None 0 — — — — — — — DRY_COIL_OUTPUT — 1— — — — — — None — 0 — — — — — — TXD — — 1 — — — — — None — — 0 — — — —— ARC_SUPPRESSOR_LOCK — — — 1 — — — — None — — — 0 — — — — Reserved — —— — 1 — — — None — — — — 0 — — — SIGNAL_INDICATOR_OUTPUT2 — — — — — 1 —— None — — — — — 0 — — SIGNAL_INDICATOR_OUTPUT — — — — — — 1 — None — —— — — — 0 — Reserved — — — — — — — 1 None — — — — — — — 0

In some aspects, a state register (illustrated in TABLE 15) may beconfigured to contain the data array pointers for the selected stateinformation.

In some aspects, the following Read and Write commands may be used inconnection with the state register: Read @ 0x6E, and Write @ 0x2E.

TABLE 15 State Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0 WET_COIL_ON1 — — — — — — — None 0 — — — — — — — WET_COIL_OPN — 1 — — — — — — None —0 — — — — — — WET_COIL_OFF — — 1 — — — — — None — — 0 — — — — —DRY_COIL_ON — — — 1 — — — — None — — — 0 — — — — DRY_COIL_OPN — — — — 1— — — None — — — — 0 — — — DRY_COIL_OFF — — — — — 1 — — None — — — — — 0— — DRIVER_INPUT_ON — — — — — — 1 — None — — — — — — 0 —DRIVER_INPUT_OFF — — — — — — — 1 None — — — — — — — 0

In some aspects, a statistics register (illustrated in TABLE 16) may beconfigured to contain the data array pointers for the selectedstatistics information.

In some aspects, the following Read and Write commands may be used inconnection with the statistics register: Read @ 0x6F; and Write @ 0x2F.

TABLE 16 Statistics Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0 STATUS1 — — — — — — — None 0 — — — — — — — STATE — 1 — — — — — — None — 0 — —— — — — MODE — — 1 — — — — — None — — 0 — — — — — FAULT — — — 1 — — — —None — — — 0 — — — — OUTPUT — — — — 1 — — — None — — — — 0 — — — INPUT —— — — — 1 — — None — — — — — 0 — — DRIVER — — — — — — 1 — None — — — — —— 0 — MODE — — — — — — — 1 None — — — — — — — 0

In some aspects, a status register (illustrated in TABLE 17) may beconfigured to contain the data array pointers for the selected statusinformation.

In some aspects, the following Read and Write commands may be used inconnection with the status register: Read @ 0x70, and Write @ 0x30.

TABLE 17 Status Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0 CYCLE_COUNT1 — — — — — — — None 0 — — — — — — — OPERATION_HALTED — 1 — — — — — —None — 0 — — — — — — SYSTEM_READY — — 1 — — — — — None — — 0 — — — — —FAILURES — — — 1 — — — — None — — — 0 — — — — FAILURE — — — — 1 — — —None — — — — 0 — — — FAULTS — — — — — 1 — — None — — — — — 0 — — FAULT —— — — — — 1 — None — — — — — — 0 — ALL_SYSTEMS_OK — — — — — — — 1 None —— — — — — — 0

In some aspects, a version register (illustrated in TABLE 18) may beconfigured to contain the data array pointers for the versioninformation.

In some aspects, the following Read and Write commands may be used inconnection with the version register: Read @ 0x71, and Write @ 0x31.

TABLE 18 Version Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0PCB_REVISION 1 — — — — — — — None 0 — — — — — — — ASSEMBLY_REVISION — 1— — — — — — None — 0 — — — — — — DATE_CODE — — 1 — — — — — None — — 0 —— — — — LOT_NUMBER — — — 1 — — — — None — — — 0 — — — — SERIAL_NUMBER —— — — 1 — — — None — — — — 0 — — — HARDWARE_VERSION — — — — — 1 — — None— — — — — 0 — — SOFTWARE_VERSION — — — — — — 1 — None — — — — — — 0 —FIRMWARE_VERSION — — — — — — — 1 None — — — — — — — 0

In some aspects, a wet coil output delay timer register (illustrated inTABLE 19) may be configured to contain the values for the wet delaytiming.

In some aspects, the following Read and Write commands may be used inconnection with the wet coil output delay timer register: Read @ 0x72,and Write @ 0x32.

TABLE 19 Wet Coil Output Delay Timer Register BIT NUMBER VALUE 7 6 5 4 32 1 0 Maximum: 2550 ms 1 1 1 1 1 1 1 1 Default: 100 ms 0 0 0 0 1 0 1 0Minimum: 0 ms 0 0 0 0 0 0 0 0

In some aspects, a switch debounce timer register (illustrated in TABLE20) may be configured to contain a one or more-byte value, such as thevalues for the switch debounce timing.

In some aspects, the following Read and Write commands may be used inconnection with the switch debounce timer register: Read @ 0x73, andWrite @0x33.

TABLE 20 Switch Debounce Timer Register BIT NUMBER VALUE 7 6 5 4 3 2 1 0Maximum: 255 ms 1 1 1 1 1 1 1 1 Default: 10 ms 0 0 0 0 1 0 1 0 Minimum:0 ms 0 0 0 0 0 0 0 0

In some aspects, a receive data delay timer register (illustrated inTABLE 21) may be configured to contain one or more-byte value.

In some aspects, the following Read and Write commands may be used inconnection with the receive data delay timer register: Read @ 0x74, andWrite @0x34.

TABLE 21 Receive Data Delay Timer Register BIT NUMBER VALUE 7 6 5 4 3 21 0 Maximum: 255 ms 1 1 1 1 1 1 1 1 Default: 10 ms 0 0 0 0 1 0 1 0Minimum: 0 ms 0 0 0 0 0 0 0 0

In some aspects, a transmit data delay timer register (illustrated inTABLE 22) may be configured to contain one or more-byte value.

In some aspects, the following Read and Write commands may be used inconnection with the transmit data delay timer register: Read @ 0x75, andWrite @ 0x35.

TABLE 22 Transmit Data Delay Timer Register BIT NUMBER VALUE 7 6 5 4 3 21 0 Maximum: 255 ms 1 1 1 1 1 1 1 1 Default: 10 ms 0 0 0 0 1 0 1 0Minimum: 0 ms 0 0 0 0 0 0 0 0

In some aspects, a wet coil current input delay timer register(illustrated in TABLE 23) may be configured to contain the values forthe wet coil output timing.

In some aspects, the following Read and Write commands may be used inconnection with the wet coil current input delay timer register: Read @0x76, and Write @ 0x36.

TABLE 23 Wet Coil Current Input Delay Timer Register BIT NUMBER VALUE 76 5 4 3 2 1 0 Maximum: 255 ms 1 1 1 1 1 1 1 1 Default: 10 ms 0 0 0 0 1 01 0 Minimum: 0 ms 0 0 0 0 0 0 0 0

In some aspects, a dry coil current input delay timer register(illustrated in TABLE 24) may be configured to contain a one ormore-byte value.

In some aspects, the following Read and Write commands may be used inconnection with the dry coil current input delay timer register: Read @0x77, and Write @ 0x37.

TABLE 24 Dry Coil Current Input Delay Timer Register BIT NUMBER VALUE 76 5 4 3 2 1 0 Maximum: 255 ms 1 1 1 1 1 1 1 1 Default: 10 ms 0 0 0 0 1 01 0 Minimum: 0 ms 0 0 0 0 0 0 0 0

In some aspects, a signal indicator output delay timer register(illustrated in TABLE 25) may be configured to contain a one ormore-byte value.

In some aspects, the following Read and Write commands may be used inconnection with the signal indicator output delay timer register: Read @0x78, and Write @ 0x38.

TABLE 25 Signal Indicator Output Delay Timer Register BIT NUMBER VALUE 76 5 4 3 2 1 0 Maximum: 255 ms 1 1 1 1 1 1 1 1 Default: 10 ms 0 0 0 0 1 01 0 Minimum: 0 ms 0 0 0 0 0 0 0 0

In some aspects, a sensor input register (illustrated in TABLE 26) maybe configured to contain the data bits for the selected sensor status.

In some aspects, the following Read and Write commands may be used inconnection with the sensor input register: Read @ 0x79, and Write @0x39.

TABLE 26 Sensor Input Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0Reserved 1 — — — — — — — None 0 — — — — — — — Reserved — 1 — — — — — —None — 0 — — — — — — Reserved — — 1 — — — — — None — — 0 — — — — —Reserved — — — 1 — — — — None — — — 0 — — — — COIL_SIGNAL_PRESENT — — —— 1 — — — None — — — — 0 — — — WET_CONTACT_CURRENT_ — — — — — 1 — —SENSOR_BIT None — — — — — 0 — — WET_CONTACT_VOLTAGE_ — — — — — — 1 —SENSOR_BIT None — — — — — — 0 — OCP_VOLTAGE_SENSOR_BIT — — — — — — — 1None — — — — — — — 0

In some aspects, an overcurrent protection voltage sensor register(illustrated in TABLE 27) may be configured to contain a one ormore-byte value.

In some aspects, the following Read and Write commands may be used inconnection with the overcurrent protection (OCP) voltage sensorregister: Read @ 0x7A, and Write @ 0x3A.

TABLE 27 OCP Voltage Sensor Register BIT NUMBER VALUE 7 6 5 4 3 2 1 0Maximum: Max Volts 1 1 1 1 1 1 1 1 Default: none x x x x x x x xMinimum: Min Volts 0 0 0 0 0 0 0 0

In some aspects, a wet contact voltage sensor register (illustrated inTABLE 28) may be configured to contain a one or more-byte value. Thevalue may be expressed for example but not limited to as average, mean,median, rms or peak.

In some aspects, the following Read and Write commands may be used inconnection with the wet contact voltage sensor register: Read @ 0x7B,and Write @ 0x3B.

TABLE 28 Wet Contact Voltage Sensor Register BIT NUMBER VALUE 7 6 5 4 32 1 0 Maximum : Max Volts 1 1 1 1 1 1 1 1 Default: none x x x x x x x xMinimum: Min Volts 0 0 0 0 0 0 0 0

In some aspects, a wet contact current sensor register (illustrated inTABLE 29) may be configured to contain a one or more-byte value. Thevalue may be expressed for example but not limited to as average, mean,median, rms or peak.

In some aspects, the following Read and Write commands may be used inconnection with the wet contact current sensor register: Read (a 0x7C,and Write

TABLE 29 Wet Contact Current Sensor Register BIT NUMBER VALUE 7 6 5 4 32 1 0 Maximum: Max Amps 1 1 1 1 1 1 1 1 Default: none x x x x x x x xMinimum: Min Amps 0 0 0 0 0 0 0 0

In some aspects, a fault arc register (illustrated in TABLE 30) may beconfigured to contain the data bits for the selected sensor status.

In some aspects, the following Read and Write commands may be used inconnection with the fault arc parameter register: Read @ 0x7D, and Write@0x3D.

TABLE 30 Fault Arc Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0FAULT_ARC_ENERGY 1 — — — — — — — None 0 — — — — — — — FAULT_ARC_DURATION— 1 — — — — — — None — 0 — — — — — — FAULT_ARC_POWER — — 1 — — — — —None — — 0 — — — — — FAULT_ARC_RESISTANCE_ — — — 1 — — — — GRADIENT None— — — 0 — — — — FAULT_ARC_RESISTANCE — — — — 1 — — — None — — — — 0 — —— FAULT_ARC_CURREINT — — — — — 1 — — None — — — — — 0 — —FAULT_ARC_VOLTAGE_ — — — — — — 1 — GRADIENT None — — — — — — 0 —FAULT_ARC_VOLTAGE — — — — — — — 1 None — — — — — — — 0

In some aspects, an amperage trip point register (illustrated in TABLE31) may be configured to contain the one or more-byte value for thespecific trip point setting. The value may be expressed for example butnot limited to as average, mean, median, rms or peak.

In some aspects, the following Read and Write commands may be used inconnection with the amperage trip point register: Read @ 0x7E, and Write@0x3E.

TABLE 31 AMPERAGE TRIP POINT REGSITER BIT NUMBER VALUE 7 6 5 4 3 2 1 0Maximum: Max Amps 1 1 1 1 1 1 1 1 Set-Amperage: none selected x x x x xx x x Minimum: Min Amps 0 0 0 0 0 0 0 0

In some aspects, an amperage trip delay register (illustrated in TABLE32) may be configured to contain the one or more-byte value for thespecific trip point setting. The value may be expressed for example butnot limited to as average, mean, median, rms or peak.

In some aspects, the following Read and Write commands may be used inconnection with the amperage trip delay register: Read @ 0x7F, and Write@0x3F.

TABLE 32 Amperage Trip Delay Register BIT NUMBER VALUE 7 6 5 4 3 2 1 0Maximum: 255 ms 1 1 1 1 1 1 1 1 Set-Amperage Trip Delay: none selected xx x x x x x x Minimum: 0 ms 0 0 0 0 0 0 0 0

In some aspects, a fault arc voltage register (illustrated in TABLE 33)may be configured to contain a one or more-byte value. The value may beexpressed for example but not limited to as average, mean, median, rmsor peak.

In some aspects, the following Read and Write commands may be used inconnection with the fault arc voltage register: Read @ 0x80, and Write @0x40.

TABLE 33 Fault Arc Voltage Register BIT NUMBER VALUE 7 6 5 4 3 2 1 0Maximum: Max Volts 1 1 1 1 1 1 1 1 Default: none x x x x x x x xMinimum: Min Volts 0 0 0 0 0 0 0 0

In some aspects, a fault arc voltage gradient register (illustrated inTABLE 34) may be configured to contain a one or more-byte value. Thevalue may be expressed for example but not limited to as average, mean,median, rms, and/or peak.

In some aspects, the following Read and Write commands may be used inconnection with the fault arc voltage gradient register: Read @ 0x81,and Write 6b, 0x41.

TABLE 34 Fault Arc Voltage Gradient Register BIT NUMBER VALUE 7 6 5 4 32 1 0 Maximum: Max dV/dt 1 1 1 1 1 1 1 1 Default: none x x x x x x x xMinimum: Min dV/dt 0 0 0 0 0 0 0 0

In some aspects, a fault arc current register (illustrated in TABLE 35)may be configured to contain a one or more-byte value. The value may beexpressed for example but not limited to as average, mean, median, rms,or peak.

In some aspects, the following Read and Write commands may be used inconnection with the fault arc current register: Read @ 0x82, and Write @0x42.

TABLE 35 Fault Arc Current Register BIT NUMBER VALUE 7 6 5 4 3 2 1 0Maximum: Max Amps 1 1 1 1 1 1 1 1 Default: none x x x x x x x x Minimum:Min Amps 0 0 0 0 0 0 0 0

In some aspects, a fault arc resistance register (illustrated in TABLE36) may be configured to contain a one or more-byte value. The value maybe expressed for example but not limited to as average, mean, median,rms or peak.

In some aspects, the following Read and Write commands may be used inconnection with the fault arc resistance register: Read @ 0x83, andWrite @0x43.

TABLE 36 Fault Are Resistance Register BIT NUMBER VALUE 7 6 5 4 3 2 1 0Maximum: Max Ohms 1 1 1 1 1 1 1 1 Default: none x x x x x x x x Minimum:Min Ohms 0 0 0 0 0 0 0 0

In some aspects, a fault arc resistance gradient register (illustratedin TABLE 37) may be configured to contain a one or more-byte value. Thevalue may be expressed for example but not limited to as average, mean,median, rms, or peak.

In some aspects, the following Read and Write commands may be used inconnection with the fault arc resistance gradient register: Read @ 0x84,and Write @ 0x44.

TABLE 37 Fault Arc Resistance Gradient Register BIT NUMBER VALUE 7 6 5 43 2 1 0 Maximum: Max dΩ/dt 1 1 1 1 1 1 1 1 Default: none x x x x x x x xMinimum: Min dΩ/dt 0 0 0 0 0 0 0 0

In some aspects, a fault arc power register (illustrated in TABLE 38)may be configured to contain a one or more-byte value. The value may beexpressed for example but not limited to as average, mean, median, rmsor peak.

In some aspects, the following Read and Write commands may be used inconnection with the fault arc power register: Read @ 0x85, and Write @0x45.

TABLE 38 Fault Arc Power Register BIT NUMBER VALUE 7 6 5 4 3 2 1 0Maximum: Max Watts 1 1 1 1 1 1 1 1 Default: none x x x x x x x xMinimum: Min Watts 0 0 0 0 0 0 0 0

In some aspects, a fault arc duration register (illustrated in TABLE 39)may be configured to contain a one or more-byte value. The value may beexpressed for example but not limited to as average, mean, median, rms,or peak.

In some aspects, the following Read and Write commands may be used inconnection with the fault arc duration register: Read @ 0x86, and Write@ 0x46.

TABLE 39 Fault Arc Duration Register BIT NUMBER VALUE 7 6 5 4 3 2 1 0Maximum: Max seconds 1 1 1 1 1 1 1 1 Default: none x x x x x x x xMinimum: Min seconds 0 0 0 0 0 0 0 0

In some aspects, a fault arc energy register (illustrated in TABLE 40)may be configured to contain a one or more-byte value. The value may beexpressed for example but not limited to as average, mean, median, rmsor peak.

In some aspects, the following Read and Write commands may be used inconnection with the fault arc energy register: Read @ 0x87, and Write @0x47.

TABLE 40 Fault Arc Energy Register BIT NUMBER VALUE 7 6 5 4 3 2 1 0Maximum: Max Joules 1 1 1 1 1 1 1 1 Default: none x x x x x x x xMinimum: Min Joules 0 0 0 0 0 0 0 0

In some aspects, a break arc register (illustrated in TABLE 41) may beconfigured to contain a one or more-byte value. In some aspects, thefollowing Read and Write commands may be used in connection with thebreak arc register: Read @ 0x88, and Write @ 0x48.

TABLE 41 Break Arc Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0BREAK_ARC_ENERGY 1 — — — — — — — None 0 — — — — — — — BREAK_ARC_DURATION— 1 — — — — — — None — 0 — — — — — — BREAK_ARC_POWER — — 1 — — — — —None — — 0 — — — — — BREAK_ARC_RESISTANCE_GRADIENT — — — 1 — — — — None— — — 0 — — — — BREAK_ARC_RESISTANCE — — — — 1 — — — None — — — — 0 — —— BREAK_ARC_CURRENT — — — — — 1 — — None — — — — — 0 — —BREAK_ARC_VOLTAGE_GRADIENT — — — — — — 1 — None — — — — — — 0 —BREAK_ARC_VOLTAGE — — — — — — — 1 None — — — — — — — 0

In some aspects, a make arc register (illustrated in TABLE 42) may beconfigured to contain a one or more-byte value. In some aspects, thefollowing Read and Write commands may be used in connection with themake arc register: Read @ 0x89, and Write @ 0x49.

TABLE 42 Make Arc Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0MAKE_ARC_ENERGY 1 — — — — — — — None 0 — — — — — — — MAKE_ARC_DURATION —1 — — — — — — None — 0 — — — — — — MAKE_ARC_POWER — — 1 — — — — — None —— 0 — — — — — MAKE_ARC_RESISTANCE_GRADIENT — — — 1 — — — — None — — — 0— — — — MAKE_ARC_RESISTANCE — — — — 1 — — — None — — — — 0 — — —MAKE_ARC_CURRENT — — — — — 1 — — None — — — — — 0 — —MAKE_ARC_VOLTAGE_GRADIENT — — — — — — 1 — None — — — — — — 0 —MAKE_ARC_VOLTAGE — — — — — — — 1 None — — — — — — — 0

In some aspects, a contact register (illustrated in TABLE 43) may beconfigured to contain a one or more-byte value. In some aspects, thefollowing Read and Write commands may be used in connection with thecontact register:

TABLE 43 Contact Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0CONTACT_HISTORY 1 — — — — — — — None 0 — — — — — — — CONTACT_STATISTICS— 1 — — — — — — None — 0 — — — — — — CONTACT_ENERGY — — 1 — — — — — None— — 0 — — — — — CONTACT_ON_DURATION — — — 1 — — — — None — — — 0 — — — —CONTACT_POWER — — — — 1 — — — None — — — — 0 — — — CONTACT_FREQUENCY — —— — — 1 — — None — — — — — 0 — — CONTACT_VOLTAGE — — — — — — 1 — None —— — — — — 0 — CONTACT_CURRENT — — — — — — — 1 None — — — — — — — 0

In some aspects, a contact cycle register (illustrated in TABLE 44) maybe configured to contain a one or more-byte value. In some aspects, thefollowing Read and Write commands may be used in connection with thecontact cycle register. Read @ 0x8B, and Write @ 0x4B.

TABLE 44 Contact Cycle Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0CONTACT_CYCLE_HISTORY 1 — — — — — — — None 0 — — — — — — —CONTACT_CYCLE_STATISTICS — 1 — — — — — — None — 0 — — — — — —CONTACT_CYCLE_DUTY_CYCLE — — 1 — — — — — None — — 0 — — — — —CONTACT_CYCLE_ON_DURATION — — — 1 — — — — None — — — 0 — — — —CONTACT_CYCLE_OFF_DURATION — — — — 1 — — — None — — — — 0 — — —CONTACT_CYCLE_FREQUENCY — — — — — 1 — — None — — — — — 0 — —CONTACT_CYCLE_TIME — — — — — — 1 — None — — — — — — 0 —CONTACT_CYCLE_COUNT — — — — — — — 1 None — — — — — — — 0

In some aspects, a contact stick register (illustrated in TABLE 45) maybe configured to contain a one or more-byte value. In some aspects, thefollowing Read and Write commands may be used in connection with thecontact stick register: Read @ 0x8C, and Write @˜ 0x4C.

TABLE 45 Contact Stick Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0CONTACT_STICK_HISTORY 1 — — — — — — — None 0 — — — — — — —CONTACT_STICK_STATISTICS — 1 — — — — — — None — 0 — — — — — —CONTACT_STICK_REFERENCE_WOO — — 1 — — — — — None — — 0 — — — — —CONTACT_STICK_WINDOW — — — 1 — — — — None — — — 0 — — — —CONTACT_STICK_DURATION_CREST_FACTOR — — — — 1 — — — None — — — — 0 — — —CONTACT_PEAK_STICK_DURATION — — — — — 1 — — None — — — — — 0 — —CONTACT_AVERAGE_STICK_DURATION — — — — — — 1 — None — — — — — — 0 —CONTACT_STICK_DURATION — — — — — — — 1 None — — — — — — — 0

In some aspects, a contact health register (illustrated in TABLE 46) maybe configured to contain a one or more-byte value. In some aspects, thefollowing Read and Write commands may be used in connection with thecontact health register: Read @ 0x8D, and Write @ 0x4D.

TABLE 46 Contact Health Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0CONTACT_HEALTH_HISTORY 1 — — — — — — — None 0 — — — — — — —CONTACT_HEALTH_STATISTICS — 1 — — — — — — None — 0 — — — — — —CONTACT_HEALTH_FAILURE — — 1 — — — — — None — — 0 — — — — —CONTACT_HEALTH_REPLACE — — — 1 — — — — None — — — 0 — — — —CONTACT_HEALTH_POOR — — — — 1 — — — None — — — — 0 — — —CONTACT_HEALT_AVERAGE — — — — — 1 — — None — — — — — 0 — —CONTACT_HEALTH_GOOD — — — — — — 1 — None — — — — — — 0 —CONTACT_STICK_NEW — — — — — — — 1 None — — — — — — — 0

In some aspects, a contact health assessment register (illustrated inTABLE 47) may be configured to contain a one or more-byte value. In someaspects, the following Read and Write commands may be used in connectionwith the contact health assessment register: Read @ 0x8E, and Write @0x4E.

TABLE 47 Contact Health Assessment Register BIT NUMBER VALUE 7 6 5 4 3 21 0 Maximum: 100% healthy 1 1 1 1 1 1 1 1 Default: none x x x x x x x xMinimum: 0% healthy 0 0 0 0 0 0 0 0

In some aspects, a contact fault register (illustrated in TABLE 48) maybe configured to contain a one or more-byte value. In some aspects, thefollowing Read and Write commands may be used in connection with thecontact fault register: Read @ 0x8F, and Write @ 0x4F.

TABLE 48 Contact Fault Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0CONTACT_FAULT_HISTORY 1 — — — — — — — None 0 — — — — — — — CONTACT_FAULT _STATISTICS — 1 — — — — — — None — 0 — — — — — — CONTACT_ FAULT_ALARM — — 1 — — — — — None — — 0 — — — — — CONTACT_ FAULT _CLEARING — —— 1 — — — — None — — — 0 — — — — CONTACT_ FAULT _FLASH_CODE — — — — 1 —— — None — — — — 0 — — — CONTACT_ FAULT _CODE — — — — — 1 — — None — — —— — 0 — — CONTACT_ FAULT _ALERT — — — — — — 1 — None — — — — — — 0 —CONTACT_ FAULT _DETECTION — — — — — — — 1 None — — — — — — — 0

In some aspects, a contact failure register (illustrated in TABLE 49)may be configured to contain a one or more-byte value. In some aspects,the following Read and Write commands may be used in connection with thecontact failure register: Read @ 0x90, and Write @ 0x50.

TABLE 49 Contact Failure Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0CONTACT_ FAILURE _HISTORY 1 — — — — — — — None 0 — — — — — — — CONTACT_FAILURE _STATISTICS — 1 — — — — — — None — 0 — — — — — — CONTACT_FAILURE _ALARM — — 1 — — — — — None — — 0 — — — — — CONTACT_ FAILURE_CLEARING — — — 1 — — — — None — — — 0 — — — — CONTACT_ FAILURE_FLASH_CODE — — — — 1 — — — None — — — — 0 — — — CONTACT_ FAILURE _CODE— — — — — 1 — — None — — — — — 0 — — CONTACT_ FAILURE _ALERT — — — — — —1 — None — — — — — — 0 — CONTACT_ FAILURE _DETECTION — — — — — — — 1None — — — — — — — 0

In some aspects, a make bounce arc register (illustrated in TABLE 50)may be configured to contain a one or more-byte value. In some aspects,the following Read and Write commands may be used in connection with themake bounce arc register: Read @ 0x91, and Write @ 0x51.

TABLE 50 Make Bounce Arc Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0MAKE_BOUNCE_ARC_ENERGY 1 — — — — — — — None 0 — — — — — — —MAKE_BOUNCE_ARC_DURATION — 1 — — — — — — None — 0 — — — — — —MAKE_BOUNCE_ARC_POWER — — 1 — — — — — None — — 0 — — — — —MAKE_BOUNCE_ARC_BOUNCES — — — 1 — — — — None — — — 0 — — — —MAKE_BOUNCE_ARC_FREQUENCY — — — — 1 — — — None — — — — 0 — — —MAKE_BOUNCE_ARC_RESISTANCE — — — — — 1 — — None — — — — — 0 — —MAKE_BOUNCE_ARC_CURRENT — — — — — — 1 — None — — — — — — 0 —MAKE_BOUNCE_ARC_VOLTAGE — — — — — — — 1 None — — — — — — — 0

In some aspects, a break bounce arc register (illustrated in TABLE 51)may be configured to contain a one or more-byte value. In some aspects,the following Read and Write commands may be used in connection with thebreak bounce arc register: Read @ 0x92, and Write @ 0x52.

TABLE 51 Break Bounce Arc Register BIT NUMBER FUNCTION 7 6 5 4 3 2 1 0BREAK_BOUNCE_ARC_ENERGY 1 — — — — — — — None 0 — — — — — — — BREAK_BOUNCE_ARC_DURATION — 1 — — — — — — None — 0 — — — — — — BREAK_BOUNCE_ARC_POWER — — 1 — — — — — None — — 0 — — — — — BREAK_BOUNCE_ARC_BOUNCES — — — 1 — — — — None — — — 0 — — — —BREAK_BOUNCE_ARC_FREQUENCY — — — — 1 — — — None — — — — 0 — — — BREAK_BOUNCE_ARC_RESISTANCE — — — — — 1 — — None — — — — — 0 — —BREAK_BOUNCE_ARC_CURRENT — — — — — — 1 — None — — — — — — 0 — BREAK_BOUNCE_ARC_VOLTAGE — — — — — — — 1 None — — — — — — — 0

FIG. 4 depicts a packaging example 400 of a health assessor, such aspower contact health assessor 1 of FIGS. 1-2, according to someembodiments.

Additional Examples

The description of the various embodiments is merely exemplary in natureand, thus, variations that do not depart from the gist of the examplesand detailed description herein are intended to be within the scope ofthe present disclosure. Such variations are not to be regarded as adeparture from the spirit and scope of the present disclosure.

Example 1 is an electrical circuit, comprising: a pair of terminalsadapted to be connected to a set of switchable contact electrodes of apower contact; a power switching circuit operatively coupled to the pairof terminals, the power switching circuit configured to switch powerfrom an external power source and to trigger activation of the set ofswitchable contact electrodes based on a first logic state signal ordeactivation of the set of switchable contact electrodes based on asecond logic state signal; a contact separation detector operativelycoupled to the pair of terminals, the contact separation detectorconfigured to determine a time of separation of the set of switchablecontact electrodes of the power contact during the deactivation; and acontroller circuit operatively coupled to the pair of terminals, thepower switching circuit, and the contact separation detector, thecontroller circuit configured to: for each contact cycle of a pluralityof contact cycles of the power contact within a first observationwindow: generate the second logic state signal to trigger thedeactivation of the set of switchable contact electrodes; and determinea contact stick duration associated with the set of switchable contactelectrodes, the contact stick duration based on a difference between atime the second logic state signal is generated and the time ofseparation during the contact cycle; determine an average contact stickduration for the first observation window based on the contact stickduration for each contact cycle within the first observation window;configure one or more additional observation windows with correspondingaverage contact stick durations based on the average stick duration forthe first observation window; and generate a health assessment for theset of switchable contact electrodes of the power contact based on asubsequent contact stick duration determined after the first observationwindow and the corresponding average contact stick durations for the oneor more additional observation windows.

In Example 2, the subject matter of Example 1 includes, wherein thecontroller circuit is configured to derive each of the correspondingaverage stick durations from an average stick duration of a previousobservation window.

In Example 3, the subject matter of Example 2 includes, wherein the oneor more additional observation windows comprise: a second observationwindow associated with a second average contact stick duration, thesecond average contact stick duration being a first multiple of theaverage contact stick duration for the first observation window; a thirdobservation window associated with a third average contact stickduration, the third average contact stick duration being a secondmultiple of the second average contact stick duration; a fourthobservation window associated with a fourth average contact stickduration, the fourth average contact stick duration being a thirdmultiple of the third average contact stick duration; a fifthobservation window associated with a fifth average contact stickduration, the fifth average contact stick duration being a fourthmultiple of the fourth average contact stick duration; and a sixthobservation window associated with a sixth average contact stickduration, the sixth average contact stick duration being a fifthmultiple of the fifth average contact stick duration.

In Example 4, the subject matter of Example 3 includes, wherein thefirst, second, third, fourth, and fifth multiples are equal to amultiple of 2.

In Example 5, the subject matter of Examples 3-4 includes, wherein eachof the observation window and the one or more additional observationwindows is associated with a contact health assessment characteristic ofa plurality of available health assessment characteristics.

In Example 6, the subject matter of Example 5 includes, wherein theplurality of health assessment characteristics include: a “newcondition” health assessment characteristic associated with the firstobservation window; a “good condition” health assessment characteristicassociated with the second observation window; an “average condition”health assessment characteristic associated with the third observationwindow; a “poor condition” health assessment characteristic associatedwith the fourth observation window; a “replace condition” healthassessment characteristic associated with the fifth observation window;and a “failed condition” health assessment characteristic associatedwith the sixth observation window.

In Example 7, the subject matter of Examples 1-6 includes, wherein thecontroller circuit is configured to configure a last one of the one ormore additional observation windows to include an observation windowwith an average contact stick duration equal to a pre-configured contactstick duration threshold associated with a failed set of switchablecontact electrodes.

In Example 8, the subject matter of Example 7 includes, wherein thepre-configured contact stick duration threshold is 1 second or greater.

In Example 9, the subject matter of Examples 3-8 includes, wherein thecontroller circuit is configured to determine a power contact stickduration crest factor (PCSDCF) for the first observation window, basedon a peak contact stick duration during the first observation windowdivided by the average contact stick duration.

In Example 10, the subject matter of Example 9 includes, wherein thecontroller circuit is configured to determine additional PCSDCFs foreach of the one or more additional observation windows, based oncorresponding peak contact stick durations and the corresponding averagecontact stick durations for each of the one or more additionalobservation windows.

In Example 11, the subject matter of Example 10 includes, wherein thecontroller circuit is configured to generate the health assessment forthe set of switchable contact electrodes of the power contact based on acomparison of a subsequent PCSDCF associated with a subsequent contactstick duration determined after the first observation window with thePCSDCF and the additional PCSDCFs.

In Example 12, the subject matter of Examples 10-11 includes, whereinthe average contact stick duration is 31.25 ms and the PCSDCF for thefirst observation window is between 128 and 32.

In Example 13, the subject matter of Example 12 includes, wherein: thesecond average contact stick duration is 62.5 ms and the PCSDCF for thesecond observation window is between 32 and 16; the third averagecontact stick duration is 125 ms and the PCSDCF for the thirdobservation window is between 16 and 8; the fourth average contact stickduration is 250 ms and the PCSDCF for the fourth observation window isbetween 8 and 4; the fifth average contact stick duration is 500 ms andthe PCSDCF for the fifth observation window is between 4 and 2, and thesixth average contact stick duration is 1000 ms and the PCSDCF for thesixth observation window is between 2 and 1.

In Example 14, the subject matter of Examples 1-13 includes, an arcsuppressor adapted to be coupled to the set of switchable contactelectrodes, the arc suppressor including the contact separationdetector.

In Example 15, the subject matter of Examples 1-14 includes, wherein thecontact separation detector comprises a voltage sensor configured tosense voltage across the switchable contact electrodes.

In Example 16, the subject matter of Example 15 includes, wherein thevoltage sensor is configured to determine the time of separation of theset of switchable contact electrodes of the power contact during thedeactivation when the voltage across the switchable contact electrodesis higher than a plasma ignition voltage level.

Example 17 is a system, comprising: a pair of terminals adapted to beconnected to a set of switchable contact electrodes of a power contact;a contact separation detector configured to determine a time ofseparation of the set of switchable contact electrodes duringdeactivation of the power contact; and a controller circuit operativelycoupled to the pair of terminals and the contact separation detector,the controller circuit configured to: determine within a firstobservation window, a plurality of contact stick durations associatedwith the set of switchable contact electrodes, wherein each contactstick duration of the plurality of contact stick durations is determinedduring a corresponding contact cycle of a plurality of contact cycles ofthe power contact within the first observation window, and is based on atime duration between generation of a logic state signal triggering thedeactivation and the time of separation of the set of switchable contactelectrodes; determine an average contact stick duration for the firstobservation window based on the plurality of contact stick durations;configure one or more additional observation windows with correspondingaverage contact stick durations, the corresponding average contact stickdurations determined based on the average stick duration for the firstobservation window; and generate a health assessment for the set ofswitchable contact electrodes of the power contact based on a subsequentcontact stick duration for a contact cycle after the first observationwindow and the corresponding average contact stick durations for the oneor more additional observation windows.

In Example 18, the subject matter of Example 17 includes, wherein thecontroller circuit is configured to derive each of the correspondingaverage stick durations from an average stick duration of a previousobservation window.

In Example 19, the subject matter of Example 18 includes, wherein theone or more additional observation windows comprise: a secondobservation window associated with a second average contact stickduration, the second average contact stick duration being a firstmultiple of the average contact stick duration for the first observationwindow; a third observation window associated with a third averagecontact stick duration, the third average contact stick duration being asecond multiple of the second average contact stick duration; a fourthobservation window associated with a fourth average contact stickduration, the fourth average contact stick duration being a thirdmultiple of the third average contact stick duration; a fifthobservation window associated with a fifth average contact stickduration, the fifth average contact stick duration being a fourthmultiple of the fourth average contact stick duration; and a sixthobservation window associated with a sixth average contact stickduration, the sixth average contact stick duration being a fifthmultiple of the fifth average contact stick duration.

In Example 20, the subject matter of Example 19 includes, wherein thefirst, second, third, fourth, and fifth multiples are equal to amultiple of 2.

In Example 21, the subject matter of Examples 19-20 includes, whereineach of the observation window and the one or more additionalobservation windows is associated with a contact health assessmentcharacteristic of a plurality of available health assessmentcharacteristics.

In Example 22, the subject matter of Example 21 includes, wherein theplurality of health assessment characteristics include: a “newcondition” health assessment characteristic associated with the firstobservation window; a “good condition” health assessment characteristicassociated with the second observation window; an “average condition”health assessment characteristic associated with the third observationwindow; a “poor condition” health assessment characteristic associatedwith the fourth observation window; a “replace condition” healthassessment characteristic associated with the fifth observation window;and a “failed condition” health assessment characteristic associatedwith the sixth observation window.

In Example 23, the subject matter of Examples 17-22 includes, whereinthe controller circuit is configured to configure a last one of the oneor more additional observation windows to include an observation windowwith an average contact stick duration equal to a pre-configured contactstick duration threshold associated with a failed set of switchablecontact electrodes.

In Example 24, the subject matter of Example 23 includes, wherein thepre-configured contact stick duration threshold is 1 second or greater.

Example 25 is a method, comprising: coupling a contact separationdetector to a pair of terminals of a power contact, the contactseparation detector configured to determine a time of separation of aset of switchable contact electrodes of the power contact duringdeactivation of the power contact based on a logic state signal;coupling a controller circuit to the pair of terminals and the contactseparation detector, the controller circuit configured to determine aplurality of stick durations associated with the set of switchablecontact electrodes, wherein each stick duration of the plurality ofstick durations is determined during a corresponding contact cycle of aplurality of contact cycles of the power contact within a firstobservation window, and is based on a time duration between generationof the logic state signal triggering the deactivation and the time ofseparation of the set of switchable contact electrodes; determining anaverage contact stick duration for the first observation window based onthe plurality of contact stick durations; configuring one or moreadditional observation windows with corresponding average contact stickdurations, the corresponding average contact stick durations determinedbased on the average stick duration for the first observation window;and generating a health assessment for the set of switchable contactelectrodes of the power contact based on a subsequent contact stickduration for a contact cycle after the first observation window and thecorresponding average contact stick durations for the one or moreadditional observation windows.

Example 26 is at least one machine-readable medium includinginstructions that, when executed by processing circuitry, cause theprocessing circuitry to perform operations to implement of any ofExamples 1-25.

Example 27 is an apparatus comprising means to implement of any ofExamples 1-25.

Example 28 is a system to implement of any of Examples 1-25.

Example 29 is a method to implement of any of Examples 1-25.

The above detailed description includes references to the accompanyingdrawings, which form a part of the detailed description. The drawingsshow, by way of illustration, specific embodiments. These embodimentsare also referred to herein as “examples.” Such examples may includeelements in addition to those shown and described. However, the presentinventor also contemplates examples in which only those elements shownand described are provided.

All publications, patents, and patent documents referred to in thisdocument are incorporated by reference herein in their entirety, asthough individually incorporated by reference. In the event ofinconsistent usages between this document and those documents soincorporated by reference, the usage in the incorporated reference(s)should be considered supplementary to that of this document; forirreconcilable inconsistencies, the usage in this document controls.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In the appended claims, the terms “including” and“in which” are used as the plain-English equivalents of the respectiveterms “comprising” and “wherein.” Also, in the following claims, theterms “including” and “comprising” are open-ended, that is, a system,device, article, or process that includes elements in addition to thoselisted after such a term in a claim are still deemed to fall within thescope of that claim. Moreover, in the following claims, the terms“first,” “second,” and “third,” etc. are used merely as labels, and arenot intended to impose numerical requirements on their objects.

In addition, techniques, systems, subsystems, and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as coupled or directly coupled orcommunicating with each other may be indirectly coupled or communicatingthrough some interface, device, or intermediate component whetherelectrically, mechanically, or otherwise. Other examples of changes,substitutions, and alterations are ascertainable by one skilled in theart and could be made without departing from the scope disclosed herein.

The above description is intended to be, and not restrictive. Forexample, the above-described examples (or one or more aspects thereof)may be used in combination with each other. Other embodiments may beused, such as by one of ordinary skill in the art upon reviewing theabove description. The Abstract is provided to comply with 37 C.F.R. §1.72(b), to allow the reader to quickly ascertain the nature of thetechnical disclosure. It is submitted with the understanding that itwill not be used to interpret or limit the scope or meaning of theclaims. In addition, in the above Detailed Description, various featuresmay be grouped together to streamline the disclosure. This should not beinterpreted as intending that an unclaimed disclosed feature isessential to any claim. Rather, the inventive subject matter may lie inless than all features of a particular disclosed embodiment. Thus, thefollowing claims are hereby incorporated into the Detailed Description,with each claim standing on its own as a separate embodiment.

What is claimed is:
 1. A system comprising: a dry contact with a firstpair of switchable electrodes, the dry contact configured to cyclethrough a make state and a break state without conducting current; a wetcontact with a second pair of switchable electrodes, the wet contactconfigured to cycle through the make state and the break state whileconducting current; an arc suppressor operatively coupled to the wetcontact and configured to extinguish an arc formed across the secondpair of switchable electrodes during the make state and the break stateof the wet contact; and a controller circuit operatively coupled to thearc suppressor and the first and second pairs of switchable electrodes,the controller circuit configured to: detect a failure of the wetcontact; determine based on the failure, a stick duration associatedwith the first pair of switchable electrodes, the stick duration basedon a duration between an instance when a coil of the dry contact isdeactivated and an instance of separation of the first pair ofswitchable electrodes during deactivation of the coil; and generate,in-situ and in real-time, health assessment for the first pair ofswitchable electrodes based on a comparison of the determined stickduration with an average stick duration associated with a window ofobservation.
 2. The system of claim 1, wherein to detect the failure,the controller circuit is configured to detect the wet contact hasfailed while in a closed position.
 3. The system of claim 1, wherein thecontroller circuit is to: record a time the failure of the wet contactis detected.
 4. The system of claim 1, wherein the controller circuit isto: output a notification of the failure of the wet contact.
 5. Thesystem of claim 1, wherein the controller circuit is to: perform aplurality of stick duration measurements associated with the first pairof switchable electrodes during the window of observation, the pluralityof stick duration measurements corresponding to a plurality of contactcycles of the first pair of switchable electrodes; and determine theaverage stick duration based on the plurality of stick durationmeasurements.
 6. The system of claim 5, wherein the controller circuitis to: configure one or more additional windows of observation when anumber of the plurality of stick duration measurements exceeds a firstthreshold.
 7. The system of claim 6, wherein a duration of the one ormore additional windows of observation is configured based on a durationof the window of observation.
 8. The system of claim 7, wherein thecontroller circuit is to: generate a failure notification when thedetermined stick duration during the one or more additional windows ofobservation exceeds a second threshold.
 9. A method for generating ahealth assessment for a pair of switchable electrodes, the methodcomprising: coupling a dry contact with a first pair of switchableelectrodes to a wet contact with a second pair of switchable electrodes,the dry contact configured to cycle through a make state and a breakstate without conducting current, and the wet contact configured tocycle through the make state and the break state while conductingcurrent; coupling an arc suppressor to the wet contact, the arcsuppressor configured to extinguish an arc formed across the second pairof switchable electrodes during the make state and the break state ofthe wet contact; detecting a failure of the wet contact; determiningbased on the failure, a stick duration associated with the first pair ofswitchable electrodes, the stick duration based on a duration between aninstance when a coil of the dry contact is deactivated and an instanceof separation of the first pair of switchable electrodes duringdeactivation of the coil; and generating, in-situ and in real-time,health assessment for the first pair of switchable electrodes based on acomparison of the determined stick duration with an average stickduration associated with a window of observation.
 10. The method ofclaim 9, wherein detecting the failure comprises: detecting the wetcontact has failed while in a closed position.
 11. The method of claim9, further comprising: recording a time the failure of the wet contactis detected.
 12. The method of claim 9, further comprising: outputting anotification of the failure of the wet contact.
 13. The method of claim9, further comprising: performing a plurality of stick durationmeasurements associated with the first pair of switchable electrodesduring the window of observation, the plurality of stick durationmeasurements corresponding to a plurality of contact cycles of the firstpair of switchable electrodes; and determining the average stickduration based on the plurality of stick duration measurements.
 14. Themethod of claim 13, further comprising: configuring one or moreadditional windows of observation when a number of the plurality ofstick duration measurements exceeds a first threshold.
 15. The method ofclaim 14, wherein a duration of the one or more additional windows ofobservation is configured based on a duration of the window ofobservation.
 16. The method of claim 15, further comprising: generatinga failure notification when the determined stick duration during the oneor more additional windows of observation exceeds a second threshold.17. An electrical circuit, comprising: a first contact with a first pairof switchable electrodes; a second contact with a second pair ofswitchable electrodes, the second contact operatively coupled to thefirst contact; an arc suppressor operatively coupled to at least one ofthe first contact and the second contact, and configured to extinguishan arc formed across at least one of the first pair and the second pairof switchable electrodes during a make state and a break state of thefirst and second contacts; and a controller circuit operatively coupledto the arc suppressor and the first and second pairs of switchableelectrodes, the controller circuit configured to: detect one of thefirst contact or the second contact is a failed contact and a remainingone is a non-failed contact; determine a stick duration associated withthe non-failed contact, the stick duration based on a duration betweenan instance when a coil of the non-failed contact is deactivated and aninstance of separation of corresponding switchable electrodes of thenon-failed contact during deactivation of the coil; and generate,in-situ and in real-time, health assessment for the switchableelectrodes of the non-failed contact based on a comparison of thedetermined stick duration with an average stick duration associated witha window of observation.
 18. The electrical circuit of claim 17, whereinthe controller circuit is to: detect one of the first contact or thesecond contact has failed while in a closed position.
 19. The electricalcircuit of claim 17, wherein the controller circuit is to: record a timethe failed contact is detected; and output a notification of the failedcontact.
 20. The electrical circuit of claim 17, wherein the controllercircuit is to: perform a plurality of stick duration measurementsassociated with the switchable electrodes of the non-failed contactduring the window of observation, the plurality of stick durationmeasurements corresponding to a plurality of contact cycles of theswitchable electrodes; and determine the average stick duration based onthe plurality of stick duration measurements.